I've just started using this and it seems quite good. You get money off or free product vouchers. Once you buy the item in the shop you scan the receipt onto the app and get the cashback. It has worked really well for me so far and the money has come in within a couple of days. Thought I would share!
I have a referral code if anyone thinks about joining and you get a free tub of Ben and Jerry's! Just download the Shopmium app and enter my referral code je8k5q
www.shopmium.com/uk/referral/je8k5q