All the equipment you need can be gotten for $60.

I just started P90X (did the first workout this morning). This is pretty much all you need (in addition to a mat and a towel). Read the reviews too, it's basically the all-in-one for P90X if you don't want to buy directly from Beach Body (much more expensive due to superfluous equipment).

Edit: I have Bowflex Dumbbells but even those can take a beat to change the weights on. The resistance bands are the easiest when momentum is important.