If you accumulate bing points for searching, MS are currently giving you a 100GB skydrive expansion for 100 points (1$). It looks like you can buy multiple to share with friends and family. (I bought 2)
http://www.bing.com/rewards/redeem/000100000056?meru=http%253a%252f%252fwww.bing.com%252f
http://www.bing.com/rewards/redeem/000100000056?meru=http%253a%252f%252fwww.bing.com%252f