Microsoft will give you 35% of a purchase you make from eBay instantly, with no catches.
- go to www.live.com
- then do a search for something you want to buy "cheap xbox 360" "cheap PS3" "cheap wii" etc
- there's a chance you'll see an ad for getting the 35% off with eBay. If you don't see it right away, just keep refreshing until you do
- click on the ad and from there you have to buy something from eBay using "buy it now" and transfer money using PayPal
- within 60 days, Microsoft will send you 35% of the list price
- must be over 18
- must be in the United States
- can use up to 3 times
Here's the thread on slickdeals.