Any half decient Digi cam would work, you will want to get a few filters to make things look smoother, and all around less Amature. Also you will want a cam that can do extreme closeups without any blurring, a very key feature for most porn
At the price your limited to you wont be able to spend much on the cam itself because you will want to put a lot of time effort and cash into your Sets and backgrounds, it seems stupid but from doing Event videos (never tackled a porn) I know that a good set and good lighting can make the pic / video 100x better.