search it.. the numbers vary. i was thinking the same myself and wondering if it was better to go in with pieces in hand and installing it myself at home. or go with one piece at a time whenever extra money becomes available.
If you get it painted then put it on I would guess somewhere in the 500-1k range for a decent paint job. If you want them to install it and paint it (as in full car) I would say at least 4500. But once again it varies those are the prices around my area though.
A few things that you must consider. How much labor it will cost to blend the body kit to your car so it matches, the labor to prep (wetsand, filler, etc), the labor to fit, modify the holes, and a whole bunch of other stuff. THere's also parts, and that includes but not limited to an epoxy based prime/sealer (for urethane stuff), base coat, and then clearcoat. There is also labor to wetsand and compound everything afterwards for a mirror shine.
What I'm trying to say is different shops charge different prices and it also depends on your area. If you want it done right (body kit stays on, paint matches), I would charge around 800-1000 bucks. A 600 paint job to me is paint is a shade or 2 off, the surface still has some imperfections, the clear coat still is orange peely, has dust particles in it, and is still rough.
One thing I also don't recommend you doing is haggling prices because they will skimp on paint/supplies. You won't notice at first but cheap basecoat and clear will fade EASILY over the course of just a few weeks.
There are also too many factors to account for to give you a good estimate.