For $650 you can not get a decent full suspension bike. For that price point, get a hardtail, seriously.
Im interested in freeride and downhilling, so if any kind of trip for that gets put together, let me know
sorry, I disagree. My 02 Kona Stinky with a couple light mods was 500 bucks off craigslist. my Dirt jumper fork was another 100 bucks. You can do it you just have to be patient.
If you only have that much money your better off buying used. Lots of people buy full suspension bikes, ride them once, and then decide its not for them and sell them cheap.