Cheapest hard drives in the UK 2026 - Ranked by Price Per TB

£/TB	Price	Size	Tech	Form Factor	Condition	Description	Rating	Reviews
£76.67	£230.00	3 TB	HDD	3.5"	New	Seagate ST3000VN000 - (3TB) 3.5 inch NAS Hard Drive (5900rpm) 6Gb/s SATA 64MB (Internal) Buy	★★★★☆ 4.1	1,308
£76.68	£1,226.81	16 TB	HDD	External	New	UnionSine External Hard Drive 16TB 3.5" Desktop HDD USB3.0 Storage Compatible for PC, Mac, TV, Desktop, Laptop(Black) HD3513 Buy	★★★★☆ 4.4	655
£76.73	£153.45	2 TB	HDD	3.5"	New	Seagate Constellation ES 2 TB 7200 RPM SATA 3 GB/s 64 MB Cache 3.5-Inch Hard Drive - ST32000644NS Buy	★★★★☆ 4.2	226
£76.81	£921.68	12 TB	HDD	3.5"	New	WD Purple 12TB Surveillance 3.5 Inch SATA 6 Gb/s Hard Disk Drive with Allframe 4K Technology - 360TB/yr, 256MB Cache 7200rpm - WD121PURZ Buy	★★★★☆ 4.4	2,280
£76.95	£153.90+35.0% 24h	2 TB	HDD	3.5"	New	WD Red Plus 2TB NAS 3.5" Internal Hard Drive - 5400 RPM Class, SATA 6Gb/s, CMR, 64MB Cache Buy	★★★★½ 4.7	234
£77.29	£309.16-1.7% 24h	4 TB	HDD	External	New	TOSHIBA Canvio Flex 4TB Portable External Hard Drive USB-C USB 3.0, Silver for PC, Mac, & Tablet - HDTX140XSCCA Buy	★★★★½ 4.6	8,148
£77.39	£928.69	12 TB	HDD	3.5"	New	Toshiba N300 PRO 12TB Large-Sized Business NAS (up to 24 bays) 3.5-Inch Internal Hard Drive - Up to 300 TB/year Workload Rate CMR SATA 6 GB/s 7200 RPM 512 MB Cache - HDWG51CXZSTB Buy	★★★★☆ 4.4	205
£77.50	£154.99	2 TB	HDD	3.5"	New	SkyHawk 2TB Internal Hard Drive HDD Buy	★★★★☆ 4.0	81
£77.62	£38.81	500 GB	HDD	2.5"	New	Western Digital WD5000LPLX - 500GB BLACK 32MB 7MM - 2.5IN SATA 6GB/S 7200RPM Buy	★★★★★ 5.0	2
£77.83	£311.30-9.5% 24h	4 TB	HDD	3.5"	New	Western Digital WD Gold WD4004FRYZ 4TB Buy	★★★★☆ 4.2	53
£77.84	£24.91	320 GB	HDD	External	New	ModusTech Facet 320GB External Hard Drive Portable USB-C/USB 3.1 Plug & Play Ultra- Slim HDD Hard drive for Backup, Gaming, PC, Mac, Laptop, PS4, Xbox, Smart TV (WHITE)Bestseller Buy	★★★★☆ 4.4	2,687
£77.96	£19.49	250 GB	HDD	External	New	Slim Portable External Hard Drive HDD – USB 3.0 TO Type-C High-Speed Storage – Compatible with Windows, Mac, Laptop, PC, Desktop, PS4, Xbox – Backup for Data, Movies, Games & Photos (White, 250 GB) Buy	★★★★☆ 4.2	43
£77.97	£155.94-4.9% 24h	2 TB	HDD	3.5"	New	Seagate Constellation ES.3 ST2000NM0033 2 TB 3.5" Internal Hard Drive ST2000NM0033-20BLK Buy	★★★★★ 5.0	3
£77.98	£38.99	500 GB	HDD	Internal	New	Hard Drive for 500GB HDD DELL INSPIRON 1525 1526 1545 N7110★ Buy	★★★★☆ 4.4	3
£78.09	£24.99	320 GB	HDD	External	New	Sonnics 320GB White External Portable Hard drive type C USB 3.1 Compatible with Windows PC, Mac, Smart tv, XBOX ONE & PS4 Buy	★★★★☆ 4.3	142
£78.14	£1,718.99	22 TB	HDD	3.5"	New	Toshiba N300 NAS HARD DRIVE 22TB BULK Serial ATA GB 7200rpm SATA 512MB Buy	★★★★★ 5.0	1
£78.45	£78.45	1 TB	HDD	2.5"	New	Seagate ST91000640NS 2.5-Inch 1 TB Constellation.2 Hard Drive - Black Buy	★★★★☆ 4.4	11
£78.76	£39.38	500 GB	HDD	External	New	HWAYO 500GB 2.5'' Portable External Hard Drive with LCD Display USB3.1 HDD Buy	★★★★☆ 4.0	66
£78.90	£39.45-1.0% 24h	500 GB	HDD	2.5"	New	Western Digital Black Mobile 500GB Serial ATA III - internal hard drives (Serial ATA III, HDD, 0-60 °C, -40-65 °C) Buy	★★★★½ 4.5	1,622
£78.96	£1,263.40	16 TB	HDD	3.5"	New	Western Digital WD161KRYZ Hard Drive 3.5 Inches 16000 GB SATA Buy	★★★★☆ 4.0	1
£79.00	£19.75	250 GB	HDD	Internal	New	Hard Disk Drive 250GB SATA II - 1 Year Warranty Buy	★★★★☆ 4.0	307
£79.00	£158.00	2 TB	HDD	2.5"	New	WD Blue 2TB Mobile 2.5" Internal Hard Drive, 5400 RPM Class, SATA 6 GB/s, 128MB Cache, 2 Year Warranty Buy	★★★★½ 4.5	3,424
£79.45	£158.89	2 TB	HDD	External	New	NEWQ Hard Drive for Phone Computer: 2 TB Photo Stick Portable Storage Device External HDD for iPhone & iPad & Android Cellphone Backup Picture \| Photo \| Video \| Data (2TB) Buy	★★★★☆ 4.0	302
£79.50	£79.50	1 TB	HDD	External	New	Toshiba Canvio Flex 1TB – Portable 2.5’’ External Hard Drive (HDD) for Mac, Windows PC, Smartphone and Tablet Use, Compatible with Most USB-C and USB-A Devices, Warm Silver (HDTX210ESCAA)100+ bought last monthUsed £79.50 · £79.50/TB Buy	★★★★☆ 4.4	210
£79.50	£238.49	3 TB	HDD	3.5"	New	Western Digital WD Red Plus 3TB SATA 6Gb/s 3.5" HDD Buy	★★★★½ 4.5	615
£79.58	£39.79	500 GB	HDD	External	New	Maxone Portable External Hard Drive 500GB 2.5" HDD - USB 3.0 Ultra Slim Aluminum HDD Backup for PC/Desktop/Laptop/TV/Chromebook/Windows - Charcoal Buy	★★★★☆ 4.4	63,740
£79.76	£159.51	2 TB	HDD	External	New	Kinhank 2TB Game Hard Drive, Built-in 120000+ Games, Batocera 33 System, External Hard Drive Compatible with Mac OS/Linux/Windows XP/7/8/10/11, Portable HDD, USB 3.0 Buy	★★★★☆ 4.2	75
£79.78	£39.89-0.1% 24h	500 GB	HDD	External	New	Maxone 500GB External Hard Drive - Portable 2.5'' USB 3.0 External HDD Buy	★★★★☆ 4.4	63,740
£79.80	£19.95	250 GB	HDD	3.5"	New	Generic 250GB \| 3.5 HDD Internal \| SATA \| Desktop Buy	★★★★☆ 4.1	13
£79.88	£239.63	3 TB	HDD	3.5"	New	Seagate (Old Model) Surveillance 3 Tb Serial ATA-600 5900 Rpm 64mb Cache 3.5 Inch Internal Hard Drive (St3000vx006) Buy	★★★★☆ 4.1	130
£79.98	£39.99	500 GB	HDD	Internal	New	Hard Drive for 500GB HP Pavilion G6 G4 G4T G6T G7 G7T Laptop Buy	★★★★½ 4.5	25
£79.98	£39.99	500 GB	HDD	3.5"	New	Toshiba DT01ACA050 500GB 3.5 inch SATA 7200RPM Internal Hard Drive Buy	★★★★☆ 4.2	204
£79.98	£39.99	500 GB	HDD	2.5"	New	500GB New Sata 2.5" hard drive for Apple Macbook & Macbook pro Buy	★★★★☆ 4.4	888
£79.99	£79.99	1 TB	HDD	External	New	Verbatim 53194 1TB Portable USB 3.0 Hard Drive - Black Buy	★★★★½ 4.6	726
£80.00	£159.99	2 TB	HDD	External	New	WD My Passport 2 TB Portable Hard Drive and Auto Backup Software for PC, Xbox One and PlayStation 4 - Red Buy	★★★★½ 4.6	3,756
£80.00	£160.00	2 TB	HDD	2.5"	New	Seagate Barracuda 2TB 2.5" HDD SATA Buy	★★★★½ 4.6	405
£80.00	£40.00	500 GB	HDD	3.5"	New	Western Digital Caviar Blue 500GB SATAIII 6Gb/s 16MB Cache 3.5 inch Internal Hard Drive OEM Buy	★★★★☆ 4.3	5,665
£80.00	£160.00	2 TB	HDD	2.5"	New	Seagate BarraCuda 2 TB Internal Hard Drive HDD – 2.5 Inch SATA 6 Gb/s 5400 RPM 128 MB Cache for PC Laptop (ST2000LM015) Buy	★★★★½ 4.6	15,404
£80.00	£160.00	2 TB	HDD	3.5"	New	Seagate ST2000VN000 2TB NAS HDD SATA III 3.5 inch Internal Hard Disk Drive for 1- to 8-Bay NAS Systems Used £99.99 · £50.00/TB Buy	★★★★☆ 4.1	1,308
£80.00	£80.00	1 TB	HDD	Internal	New	Western Digital 1TB WD RE4 1000 GB Serial ATA II Internal Hard Drive Buy	★★★★☆ 4.4	92
£80.00	£40.00	500 GB	HDD	2.5"	New	Seagate Momentus Thin 500GB 500GB SATA HARD DRIVE – 500 GB, SATA, 5400 RPM, 2.5 Laptop Hard Drive Buy	★★★★☆ 4.3	843
£80.00	£80.00	1 TB	HDD	Internal	New	HGST Travelstar 5K1000 1TB - internal hard drives (SATA, 0 - 60 °C, -4 Buy	★★★★☆ 4.2	56
£80.05	£160.09+0.8% 24h	2 TB	HDD	External	New	Intenso 6021480 Memory Play Portable Hard Drive 2TB Portable External TV Hard Drive - 2.5 Inch 5400 rpm 8MB Cache USB 3 with TV Mount Black Buy	★★★★½ 4.5	290
£80.15	£320.59+1.8% 24h	4 TB	HDD	External	New	Western Digital 4TB My Book Desktop External Hard Drive, USB 3.0, External HDD with Password Protection and Backup Software - WDBBGB0040HBK-NESN Buy	★★★★☆ 4.4	11,264
£80.19	£160.37-2.6% 24h	2 TB	HDD	External	New	LaCie Rugged USB-C 2TB External Hard Drive Portable HDD – USB 3.0 compatible, Drop Shock Dust Rain Resistant, for Mac and PC Computer Desktop Workstation Laptop, Orange Buy	★★★★½ 4.6	5,762
£80.33	£241.00	3 TB	HDD	3.5"	New	Western Digital WD3003FZEX Performance 3 TB 3.5-Inch Hard Drive - Black Buy	★★★★☆ 4.3	875
£80.62	£80.62	1 TB	HDD	External	New	YOTUO 1TB External Hard Drive, Portable Storage Expansion HDD, USB 3.0 & USB-C for PC, Mac, Desktop, Laptop, Smartphone, PS4, Xbox One, Xbox 360, Office & Game, Black Buy	★★★★☆ 4.3	1,996
£80.99	£323.97	4 TB	HDD	External	New	WD 4TB My Book external hard drive, Desktop HDD with Password Protection, USB 3.0, SuperSpeed USB, software for device management, backup, hardware encryption, Black Buy	★★★★½ 4.5	4,128
£81.00	£81.00	1 TB	HDD	3.5"	New	Western Digital WD10EZEX 3.5-Inch 1 TB SATAIII Internal Hard Drive - Black Buy	★★★★☆ 4.4	1,533
£81.00	£162.00	2 TB	HDD	2.5"	New	WD Blue 2TB Mobile 2.5" Internal Hard Drive, 5400 RPM Class, SATA 6 GB/s, 128MB Cache, 2 Year Warranty Buy	★★★★½ 4.6	140
£81.00	£162.00	2 TB	HDD	3.5"	New	WD_BLACK 2TB Performance 3.5" Internal Hard Drive - 7200 RPM Class, SATA 6 Gb/s, 64MB Cache Buy	★★★★½ 4.5	945
£81.09	£25.95	320 GB	HDD	Internal	New	320GB Internal Slim Hard Disk Drive for XBOX 360 Buy	★★★★☆ 4.4	777
£81.31	£162.61-0.2% 24h	2 TB	HDD	Internal	New	Toshiba DD Canvio Slim 2TB Hard Disk - Black Buy	★★★★½ 4.7	22
£81.41	£26.05	320 GB	HDD	External	New	Storite External Gaming Hard Drive, 2.5-Inch Portable HDD with USB 3.0, 5 Gbps Data Transfer, Compatible with PS4, PS3, PC, Android, Mac, Black, 320GB Buy	★★★★☆ 4.2	1,162
£81.50	£162.99	2 TB	HDD	3.5"	New	WD Purple 2TB for 3.5" Video Surveillance Internal Hard Drive - AllFrame™ Technology - 180TB/Year, 64MB Cache, Three Year Warranty Buy	★★★★☆ 4.4	176
£81.51	£489.04	6 TB	HDD	3.5"	New	WD Black 6TB Performance Desktop Hard Disk Drive - 7200 RPM SATA 6 Gb/s 128MB Cache 3.5 Inch - WD6001FZWX Buy	★★★★☆ 4.4	199
£81.51	£326.03+4.5% 24h	4 TB	HDD	3.5"	New	WD Red Plus 4TB NAS 3.5" Internal Hard Drive - 5400 RPM Class, SATA 6 Gb/s, CMR, 256MB Cache Buy	★★★★½ 4.5	303
£81.52	£326.06	4 TB	HDD	3.5"	New	Toshiba MG04ACA400N - Hard drive - 4 TB - internal - 3.5" - SATA 6Gb/s - NL - 7200 rpm - buffer: 128 MB Buy	★★★★☆ 4.1	57
£81.61	£326.45	4 TB	HDD	External	New	TOSHIBA Canvio Advance 4TB Portable External Hard Drive USB 3.0, Red - HDTCA40XR3CA Buy	★★★★½ 4.6	9,249
£81.72	£20.43	250 GB	HDD	Internal	New	Heayzoki Internal Hard Drive,Slim Game Console HDD Hard Drive Disk,Internal Hard Drive 250GB for XBOX 360 for XBOX 360 Slim.((250GB)) Buy	★★★★★ 5.0	1
£81.89	£81.89	1 TB	HDD	External	Warehouse	WD 1 TB Elements Portable Hard DriveBestseller Buy	★★★★½ 4.7	287,087
£81.97	£26.23	320 GB	HDD	External	New	UnionSine HD2510 Portable External Hard Drive 320GB Ultra-Thin 2.5 Inch USB 3.0 SATA HDD Storage for PC, Mac, Desktop, Laptop, Wii U, Xbox, PS4 (Black)100+ bought last month Buy	★★★★☆ 4.4	52,569
£82.13	£82.13	1 TB	HDD	2.5"	New	Western Digital Blue 1 TB SATA 2.5-Inch Hard Drive Buy	★★★★½ 4.6	7,852
£82.15	£82.15	1 TB	HDD	3.5"	New	Western Digital WD10EZEX Caviar BLUE 1000 GB Internal Buy	★★★★☆ 4.4	23
£82.23	£328.90	4 TB	HDD	3.5"	New	Toshiba N300 PRO 4TB Large-Sized Business NAS (up to 24 bays) 3.5-Inch Internal Hard Drive - Up to 300 TB/year Workload Rate CMR SATA 6 GB/s 7200 RPM 256 MB Cache - HDWG440XZSTB Buy	★★★★☆ 4.4	205
£82.32	£164.64	2 TB	HDD	3.5"	New	Seagate BarraCuda Internal Hard Drive 2TB SATA 6Gb/s 256MB Cache 3.5-Inch (ST2000DM008) Buy	★★★★☆ 4.1	124
£82.34	£658.75	8 TB	HDD	External	New	BUFFALO DriveStation 8TB High Speed 7200RPM TAA Desktop External Hard Drive USB 3.2 Buy	★★★★☆ 4.2	558
£82.35	£329.38	4 TB	HDD	External	New	Western Digital My Passport 4 TB Portable Hard Drive and Auto Backup Software for PC, Xbox One and PlayStation 4 - Black Buy	★★★★½ 4.6	3,756
£82.38	£659.00	8 TB	HDD	3.5"	New	Seagate IronWolf Pro 8 TB NAS Internal Hard Drive HDD – 3.5 Inch SATA 6 Gb/s 7200 RPM 256 MB Cache for RAID Network Attached Storage, Data Recovery Service (ST8000NE0004) Buy	★★★★☆ 4.1	39
£82.50	£495.00	6 TB	HDD	3.5"	New	Western Digital HDD Gold 6 TB SATA 256 MB 3.5 Inch Buy	★★★★☆ 4.4	2,243
£82.50	£165.00	2 TB	HDD	External	New	Transcend 2TB StoreJet 25H3 Rugged Portable HDD, One Touch Backup Buy	★★★★☆ 4.4	6,561
£82.90	£165.80	2 TB	HDD	2.5"	New	Seagate BarraCuda 2TB, Internal Hard Drive, 2.5 Inch , SATA, 6GB/s, 5.400 RPM, 128MB Cache for PC Laptop, FFP (ST2000LMZ15) Buy	★★★★½ 4.6	46,431
£82.96	£165.92	2 TB	HDD	External	New	2tb External Hard Drive,2tb Hard Drive USB 3.0 BT Card reader for Mac,PC, Desktop, Laptop, MacBook, Chromebook, Xbox One, Xbox 360 Buy	★★★★☆ 4.0	64
£83.00	£165.99	2 TB	HDD	External	New	iDiskk App-le Certified 2TB External Hard Drive for iPhone iPad Android Phones,MacBook,Computer,USB-C External Hard Disk to Backup Photos Videos Files for iPhone17/16/15/14/13/12 Buy	★★★★☆ 4.1	478
£83.00	£83.00	1 TB	HDD	2.5"	New	Seagate BarraCuda 1 TB Internal Hard Drive HDD – 2.5 Inch SATA 6 Gb/s 5400 RPM 128 MB Cache for PC Laptop (ST1000LM048) , Black Used £71.99 · £71.99/TB Buy	★★★★½ 4.6	5,967
£83.01	£166.02	2 TB	HDD	3.5"	New	Seagate 2TB IronWolf Internal NAS Hard Drive \| SATA 6 Gb/s (ST2000VNZ03) Buy	★★★★½ 4.6	423
£83.26	£83.26	1 TB	HDD	Internal	New	Western Digital Caviar Green 1TB AV 32MB Cache 5400 RPM Internal Hard Drive OEM - Sky + Compatible Upgrade Buy	★★★★☆ 4.4	11
£83.38	£166.75	2 TB	HDD	3.5"	New	Western Digital Purple 2TB Surveillance 3.5 Inch SATA 6 Gb/s Hard Disk Drive with Allframe 4K Technology - 180TB/yr, 64MB Cache, 5400rpm - WD20PURZ Buy	★★★★½ 4.6	6,590
£83.46	£83.46	1 TB	HDD	3.5"	New	Western Digital WD10EZEX - WD 3.5" 1TB SATA3 Caviar Blue Hard Drive 7200RPM 64MB Cache Buy	★★★★★ 5.0	1
£83.52	£167.03-9.4% 24h	2 TB	HDD	External	New	WD 2TB My Passport Ultra, portable external storage, external hard drive, software with defense against ransomware, backup and password protection, Works with PC, Xbox S\|X, PS5, PS4, Midnight Blue Buy	★★★★½ 4.5	11,172
£83.70	£334.80	4 TB	HDD	3.5"	New	Toshiba X300 PRO 4TB High Workload Performance for Creative Professionals 3.5-Inch Internal Hard Drive – Up to 300 TB/Year Workload Rate CMR SATA 6 GB/s 7200 RPM 512 MB Cache - HDWR740XZSTB Buy	★★★★½ 4.6	68
£83.71	£669.67	8 TB	HDD	3.5"	New	Toshiba N300 PRO 8TB Large-Sized Business NAS (up to 24 Bays) 3.5-Inch Internal Hard Drive - Up to 300 TB/Year Workload Rate CMR SATA 6 GB/s 7200 RPM 512 MB Cache - HDWG780XZSTB Buy	★★★★½ 4.5	38
£83.84	£83.84	1 TB	HDD	Internal	New	WD 1 TB Performance Hard Drive - Black Buy	★★★★½ 4.6	4,219
£83.90	£167.80	2 TB	HDD	2.5"	New	Samsung M9T 2 TB HDD 5400rpm 6.4 cm 2.5-Inch SATA II Internal Hard Drive Buy	★★★★½ 4.6	1,008
£83.98	£41.99	500 GB	HDD	Internal	New	Seagate ST500VT000 Video 500 GB Internal Buy	★★★★☆ 4.3	137
£83.98	£41.99	500 GB	HDD	2.5"	New	Seagate ST500VT000 Internal Hard Drive 500 GB (6.35 cm (2.5 Inch) 5400 rpm SATA Black Buy	★★★★☆ 4.3	424
£84.00	£42.00	500 GB	HDD	Internal	New	WD WD5000LUCT AV-25 500 GB Internal Hard Drive - Black Buy	★★★★☆ 4.3	45
£84.00	£84.00	1 TB	HDD	2.5"	New	WD 1 TB 2.5 inch SATA Internal Hard Drive - Black/Grey Buy	★★★★☆ 4.3	345
£84.00	£335.99-0.0% 24h	4 TB	HDD	External	New	WD 4 TB My Passport for Mac Portable Hard Drive - Black Buy	★★★★☆ 4.4	2,227
£84.00	£84.00	1 TB	HDD	3.5"	New	WD 1TB Desktop SATA Hard Drive - OEM - Green Buy	★★★★☆ 4.4	2,299
£84.00	£84.00	1 TB	HDD	Internal	New	WD10SPZX 1TB Internal Hard Drive Buy	★★★★☆ 4.1	374
£84.06	£84.06	1 TB	HDD	2.5"	New	WD Blue 1 TB 2.5 Inch Internal Hard Drive - 5400 RPM Class, SATA 6 Gb/s, 128 MB Cache Buy	★★★★½ 4.5	184
£84.06	£84.06	1 TB	HDD	3.5"	New	DT01ACA100 Toshiba 1tb 7200rpm 3.5inch Sata 6gbps 32mb Cache Hard Dri Buy	★★★★☆ 4.0	118
£84.15	£84.15	1 TB	HDD	3.5"	New	Seagate ST1000NM0033 Constellation ES.3 Buy	★★★★☆ 4.2	145
£84.25	£168.49+2.1% 24h	2 TB	HDD	3.5"	New	WD Western Digital Red Plus 3.5" 2000 GB Series ATA III Buy	★★★★☆ 4.4	15
£84.33	£84.33	1 TB	HDD	2.5"	New	WD Blue 1TB Mobile 2.5" Internal Hard Drive, 5400 RPM Class, SATA 6 GB/s, 128MB Cache, 2 Year Warranty Buy	★★★★½ 4.6	86
£84.46	£1,689.28	20 TB	HDD	Internal	New	OWC 20TB (20.0TB HDD 7200 RPM Drive) miniStack STX, Upgradeable,Stackable Expansion Solution and Thunderbolt Hub/Mini Dock for Mac Studio, Mac mini and Other Devices. Silver Buy	★★★★½ 4.5	22
£84.50	£169.00	2 TB	HDD	External	New	Seagate One Touch 2TB External Hard Drive Buy	★★★★☆ 4.4	844
£84.50	£169.00	2 TB	HDD	External	New	Seagate Game Drive for PS4, 2TB, Portable External Hard Drive, Compatible with PS4 and PS5 (STGD2000200), Black Buy	★★★★½ 4.7	35,238
£84.59	£84.59	1 TB	HDD	External	New	Toshiba 1TB Canvio Basics Portable External Hard Drive,USB 3.2. Gen 1, Black (HDTB410EK3AA) Buy	★★★★½ 4.7	88,611

Cheapest Hard Disk Drives (HDD) ranked by price per terabyte