I had a buddy who wanted help replacing some floor boards on the front porch on his house. I brought all of my tools, truck, etc. and we were working on it because he has no tools and honestly I would feel bad for the birds if he tried to build a birdhouse. He left to go to Lowes for more materials and I stayed working on the porch when the building inspection department pulled up. Apparently the nosy neighbor called them because she did not see a business license sticker on my truck. They asked me if this was my house, and when I said no, they started giving me a ration of shucks requesting my business license and permit for the job. I tried to explain the situation and that I was simply helping a buddy out, but ended up having to get the homeowner on the phone to explain to them that it was his house and was doing the project himself so no permit was required. They actually stopped me from being able to do any work until he returned home and showed him his ID with the address on it. I know this has no real impact on the original posters question, but my point is that someone is always watching and could get you in a pickle if you were doing it for profit I think. The only profit I was getting was the cold beer he supplied while we worked.