thenammagazine
Super Freak
Beto is offering some of his older sculpts (unpainted) if you're interested in putting together your own. But I agree with Nam with the Sideshow Jason. They've gone up in price, but compare to the other alternatives out there, it may be the best option for you for a complete figure. Be patient though, time to time you can get one at a decent price at auction or buy it now (just picked up a Part 3 mint for $169.99) which is much cheaper than the $250 or more that some of these sellers are asking for.
Yup. Avoid trying to buy them around Halloween and Christmas (Sept through Jan). If you do, on average you can easily snipe them for around $100-$150 off of ebaY. If you don't, they can chase up the price ridiculously.