This is weird but true. Microsoft has some sort of incentive going for using their Live search engine. They randomly offer discounts on certain product purchases for people who search using Live. The interesting thing is that one of the sites that they are offering the discount for is eBay. eBay sells almost anything you can imagine and so you can use the 30% discount on anything from eBay.
The process is actually quite simple. All you need to do is search from something generic and then the top advertisement bar in the browser will highlight the special live discount on eBay. You just click that link and then search for anything you want on eBay. You have to purchase the item via "Buy It Now" and you have to pay with PayPal. Neither of these conditions are particularly onerous. To see if the offer applies, simply click "Buy It Now"in the listing. This will bring you to a confirmation screen which will confirm that the discount applies and how much it is. At this point, you just complete the sale normally and you are all set! How simple is that?
Here is an article that talks more about this including more detailed step-by-step instructions. One final side note, Microsoft will take 60 days to pay you to protect against returns. That said, they will pay you in case and so there is none of this merchandise credit nonsense that we sometimes.
IMO, this is just a great deal and is too good to pass up. I already took advantage of it!