Check out this website that I found while shopping for art posters. At a website called EdgarEmdenGallery.com, when you buy something, they email you 10% of the amount as a reward certificate. Here’s the funny part. When you happen to buy a gift certificate and not use it for 90 days, they automatically cancel it and refund your money back. After that, one month later, you also get the 10% reward cash refunded!!! Now, it all depends on how you see it, of course, but you end up getting 10% on your money in 4 months. Assuming you repeat this three times, that’s 30% annual rate! (Not bad). I don't know if this is a mistake or a glitch on their part, but I don’t think they noticed this yet, because it’s still up on their website.