What is the best four wheeler for me?

In that price range you are going to be looking for a late 90s or early 00s Quad. You maybe able to find a Honda TRX300 or a Yamaha Warrior 350 in that price range. Those are both 4-strokes if you can't find something like that you could get a Polaris Trailblazer 250 2-stroke and it would have close to the same power. If you want a 4x4 you will probably not find anything in that price range.