Need 90 points for XBL... any way to get them cheap/free?

As the thread title says, I'm 90 points short on what I want to buy on Xbox Live, but I really don't want to buy 400 more points and then be in this same situation again down the road.

Are there any surveys or something similar that I can do to accumulate a few extra points? I enrolled in their Xbox Live Rewards program but that will apparently take 2 days to activate, and I'll only get 40 points out of it.

If anyone knows of a better (free) solution, I'd appreciate it. Thanks.

note that you'll get the msp from xbox rewards once you have accumulated at least 100.

You could always try and buy a bing 100msp off someone in the XBL code trading thread?