If you can find it on Amazon.com you can get it free, literally. It took me about a month to earn a $150 computer chassis (I unbox it in the video). You can get Xbox Live, movies, games, game systems, MS points, software, clothes, makeup, books and more (obviously the more it costs the longer it takes to earn but it is very easy to do). Most importantly it doesn't require a credit card or any financial info.
For a step by step guide:
http://www.ehow.com/how_5168570_use-pointsshop.html
or go straight there and sign up:
http://www.points2shop.com/index.php?ref=uin1241822713
Have fun!