If it's on the lot for 24k they probably paid more like 16-17k for it. There's HEAPS of margin in them.

I'd offer no more than 20k for it - if they laugh or don't take you seriously, ask to deal directly with the sales manager.

Another tactic that i've seen work is to ask them what they'd get as a commission if they sell it to you for 20k vs 24k, and then offer to make up the difference in cash out the back