You can pick up an compressor for under $150 that will do the job. Don't expect to be able to use it for air tools or an HVLP gun, but for an air brush or touch up gun, or even a conventional full gun (if you are patient), it will work. Because I had to move and now live in a 2 bedroom villa, I had to retire my 3hp 100l beast, but the the little 20l 2hp compressor is working just great with an air brush and a 1mm touch up gun. Just have to make sure that you have a water trap/regulator on the compressor, and a water trap/filter (these are pretty cheap) on the end of your air hose. most of the 20l and above compressors from Bunnings or Supercheap come with a regulator /water trap.
Alternatively you could probably get something used from Fleabay or Gumtree. If you are going to be doing a few of these guitars, it's probably worth the investment.