depends on what you want to do with it. I used to have a York compressor system on (I think my sig. says I still have it, but I had to take it off) with an air tank. If you want anything that will run an impact hammer, you pretty much have to go with the York set up. If you are looking for something to just air up or down then I think ARB now has an under hood that will do that, but it wont run tools and takes a while to do the job. Google Kilby Enterprise. They have a Jeep set up that might be adaptable and also google onboard air. You can do one for as much as a grand, but if you scrounge all the parts, you can do it for less, a lot less.