well, you can wait on the steam controller if you're willing to pay $60 for that.
alternatively, you can get a rock candy xbox 360 or ps3 controller for around 15 or 20 dollars. i believe they have xbone and ps4 controllers as well, but they cost more. the rock candy controllers are transparent and have no rumble motors, so if you're cool with that, it's worth the price. i have a 360 controller, and it works great.
oh, it also has the stuffty 360 d-pad, and i don't know if it's interchangeable. it can also have a funky setup procedure. it's possible that windows won't recognize it as a controller, but there's a simple fix that you can google.