They had the GamePad Pro for $6.88 at the OD I went to during lunch. They had about 5-6 of them. They also had some tilt-a-pad thing from gravis, (Basically a gamepad pro w/ tilt sensors) for $14.88 (4 of those). It's USB but I'm not sure if it's any good.
I personally don't like the gamepad pro that I have, the Up and Right button on the directional pad don't respond correctly, so, more often than not it responds diagonal up-right, when I really just want the right.
That REALLY sucks when you play the Baseball sims, and want to throw to first base and the ball keeps going to second.
For $2.88 I'd be tempted to try another just to see if it's my particular gamepad or if they all are Suck.