I just got some yellow paint matched on my 240Z. It cost $85 for a litre or so of paint enough to paint my bonnet and spoiler, this price included primer and thinners, I did get a discount as one of the blokes that works in the shop is part of the Tasmanian Datsun Owners Club.
I just took panel off my car and they took a few hours to colour match it. You could probably take an inspection hatch off.
$500 for primer, thinners, colour matched paint and clear coat is probably on the topend of the price range.
email Spectrum Car Paints spectrumpaints@bigpond.com for a comparison. It is where I got my paint from in Tassie.