Macbook Pro Power Adapter Help

Well I have a 15 inch Macbook Pro (new version), and the power adapter just stopped working. It's not the chord itself, it's just the square power adapter. I can unplug the chord from my power adapter, and plug it into a friends power adapter, and it works fine. They have a 13 inch macbook pro. I didn't know the 13 inch macbook pro's charger would work on the 15 but it does. Anyways, I've been looking for a CHEAP power adapter somewhere and am wondering if some other people could help me out with finding the cheapest one.

I'm looking at this one - http://www.amazon.com/dp/B003UPJMVU/?tag=macforums0e4-20

Would this one work? I think it might be for the older macbook pro's.

If you have a new MBP it must still be under warranty, right? If so, have Apple replace the MagSafe Charger Adapter. Less expensive versions do not work right anyway.