Just posting my success with this controller. Contrary to other threads I've seen that state difficulties in mapping keys to the controller, I have absolutely no issues mapping all game commands to this controller. And, the game plays quite nicely without the need for keyboard and mouse.

Logitech Rumblepad 2 http://www.amazon.com/Logitech-Cordless-Rumblepad-Vibration-Feedback/dp/B0002XJBGE/

(by default the controller is automatically detected by BS3 and you can walk around only with the controls. You will need to download the software from Logitech in order to map the other functions to a profile. Once the profile is created, you can even launch the game from it).

I'm sure there are some cheaper options that will also get the job done, but I'm posting what I know works for me.