This has been posted before a couple months ago, but even though you can still get this deal, Best Buy stopped advertising it. It's a 4 GB XBox 360 with Kinect for $99 if you get a 2 year, $15/month XBox Live contract. This is in-store only.
No, it won't save you money long-term, but it's less money up front and MUCH better than buying it on credit. I just got one a few minutes ago at Best Buy, so I can say for certain that the deal is still active. You won't see it on the shelves--you'll have to ask for it if you want it.