If you want to do a lot of Ethernet cabling then it is worth doing them yourself rather than buying individual cables. The lot below costs about £25 and you can make the exact length you need. A 5m ready mady is about £6. They are easy to do - loads of vids on youtube.
Cable : £17.99 (I got 200m for about the same price ages ago)
Amazon product ASIN B007JIRL8A
RJ45s 100 for £1.52
Amazon product ASIN B001D2IJLG
Crimper £2.37
Amazon product ASIN B004J02DRU
Cable Tester: £3.59
Amazon product ASIN B007CJUEDA
Cable : £17.99 (I got 200m for about the same price ages ago)
Amazon product ASIN B007JIRL8A
RJ45s 100 for £1.52
Amazon product ASIN B001D2IJLG
Crimper £2.37
Amazon product ASIN B004J02DRU
Cable Tester: £3.59
Amazon product ASIN B007CJUEDA