Been using cardyard for about a year, mainly use for Amazon uk, it has been handy to save a few pounds as uploads are frequent. Discount has varied from 3-5%; but every little helps. The code is typically delivered within 10 minutes, so no wasting time, simple and worth remembering. I find it's best to top up in advance, just in case something crops up, then I add when it's low. Give it a try, more users mean more growth, more discounts, as you can both buy and sell. Happy gifting!!!