I have signed up to www.fieldagent.com and using this site you can download an app and do store checks for products.  My plan is not to go out of my way so was pleased when a store check came up at the supermarket I was planning to go to for my shop. I had to check availability of the products take a couple of pictures and buy a couple of the products. For this I should have earnt £5 and had the value of the products refunded and I also get to keep the products.