The time to put new suspension on is when you buy it

J/K If you are looking to go on the cheap go for rough country or something similar, you will get new front springs w/bushings, rear lift blocks, ubolts (most of the time) and shocks sometimes. A lot of the cheap kits come with brake hose relocation brackets so you don't need longer lines, or atleast they used to. I have seen a lot of these kits on
ebay starting at $250 with shocks. Remember though, that they will make for a stiff ride. You willl also need dropped draglink more than likely. I got mine off
ebay from Foothills offroad for $50. It is a pro-comp unit which is normally more expensive anymore if you buy from 4wheelparts etc.
OME would be a much nicer option as they are not nearly as stiff as any lift kit made for stock hangers (no welding required). They aare also a lot more expensive though as the full OME kit will run around $100. I believe the leaf springs themselves run about $175 a pair, then you will need to hunt down u-bolts, bushings, blah blah blah, and it will be a pain in the ass, how do I know, I just did it!