It really depends on what type of tools you will be using. Some air tools consume a ton of air if used for long periods, such as saws. The nice thing about air compressors is that if you decide you need something with higher flow or a larger tank, etc., you can sell your other one. There's always a market for used compressors because people like you are just into the hobby. I had to get a huge compressor at one point because I was doing composites work and needed something to run a HVLP gelcoat gun (which flows many times more air than an HVLP paint gun). An average sized 120VAC compressor will do fine for most garage jobs though, as long as you're not doing massive customizing work with sheet metal, paint, etc.