For just one small project it may be easier to just pay someone to spray them for you? Clean paint booth setting, disposal of the leftovers, and someone who already knows how to set the gun up are all important....

I'm sure your local body shop supplier can set you up with a decent low cost paint gun that is plenty capable of working on small projects. FWIW I've seen do it yourself types on Youtube do some nice looking paint work with cheap HF paint guns as well. I'm not a big fan of HF in general, but they do have some stuff that is fairly well made for the money.