Whatever controller you get, make sure you have an analog stick and also a total of four L/R trigger buttons. Playing the game without those features would be ill-advised.
The best controller you can get would be the Logitech Rumblepad 2. It looks exactly like the Playstation 2 controller, and it vibrates. If you want to go cheaper, there's another Logitech gamepad that also looks exactly like the PS2 controller, without the vibration. I think you could get it for $19.99 or something.
Madden would detect either one of those gamepads, and automatically default to a button config that matches the Playstation control scheme.