I've been riding a bike since I could walk but only tried down hill a couple of times. I visited a bike park in France and rode with a couple of experienced riders that I managed to keep up with.
I would also say have a look in the buy sell. just type in your price range and look for good deals. If your looking low budget the Ironhorse Sunday would be good if you could find one.
According to this review, yes. Even better second hand as it's a few years old it would go cheaper. Be wary of crash damage but according to some reviews it seems to be bombproof.