If you look around you can find a deal on older top of the line compressors. I found a cabinet shop that was closing down and Bought a big Comp Air/ Kellog 220 6 horse 2 stage comp. for $300.00. I mounted it outside on a slab with a roof over it. It's pretty quiet inside the shop and runs everything I need it to. This is kinda like the one I bought.
http://yabe.chudov.com/CommpAir-Kellogg-Horizontall-Air-Compressor-5-HP-80-GAL-17786/DSC_0029.JPG
