Sassieshop was one company I did and they were good to work with.
A recommendation I would pass on is to only do the ones you would already shop if they require a purchase (some do some don't). Oh, and don't take a teenage daughter along to a clothing shop! (You'll spend much more than you'll get reimbursed - ask me how I know this)
Obviously any restaurant ones would require a purchase. I ended up being reimbursed for my meal plus a little extra when I did Subway. They did specify which sandwich to pick, but it was one I liked anyway.