when you go to a store and they ask if you have a rewards card. once you sign up, they bombard you with junk emails
I don't get a bunch of junk mail and I have a Capital One visa rewards card.I just use it for my regular shopping.I think the interest is 1 %.I recently cashed in about $31 and change and bought a Mountain Red hooded sweat shirt from L.L.Bean that retails for $49.95.So it only cost me $18 and change.