http://www.halfords.com/cycling/bike-parts/gears-drivetrain-cables/kmc-10x-shim-sram-kmc-bike-chain-links-card-of-2?_$ja=kw:drytinder%7Ctsid:40392&cm_mmc=Affiliates-_-PerformanceHorizon-_-drytinder-_-TopLink

A pretty good price as these are over £6 on Merlin cycles, yeah Chinese eBay sellers have them cheaper but they could well be seconds or fakes,

Halfords also have a promotion £5 of £30 £10 of £50 spend etc, so bulk buy with a few friends for £2.50 each if you get 10 packs