When you sign up for the bing.com rewards programme your acount is credited with 250 points. You can then use these points to get free MS points.
250 bing points = 250 MS points (you can only do it in 100 denominations)
You also get 1 point for every 2 searches (limited to 10 per day)
Not bad for free :)https://ssl.bing.com/rewards/signup/
(First time post, please be kind)