I am probably going to build a dirt jump bike from scratch very soon, and I wanted to know what are some of the cheapest/best parts for the price? I am on a pretty tight budget
Buying a lightly-used complete is always going to be a better deal than buying all the parts for a bike.
If you can find a DK Asterik on Craigslist or alike,that'll be about the cheapest,safest bet. 4130 frame that's reliable although a bit heavy. But a great starting point.
Did a few craigslist searches in Florida, and saw very few DJ bikes. Saw this one:
Specialized p.1 jump bike - $280 (Sarasota fl) As far as P bikes go, it's pretty dated. Looks like a 2004 or 2005. Then again, people really liked that bike for crossing over from trail to jumps. Not a technical skatepark riding type bike though. Also you'd probably have to replace the fork soon. So, not a great deal. http://sarasota.craigslist.org/bik/5583238285.html