Feeling a little guilty

I was surfing fabo and making macaroni salad a little while ago when there was a knock on my door. I went to the door and the man standing there says to me.. "I go by here fairly often and I've seen you working on bikes and stuff in the driveway. I have a bike in the storage facility up the street and it won't start I was wondering if you could take a look at it." I told him I'm not a mechanic but i'd be willing to help him out if I can. He told me he just put a new battery in it and it has no power to anything. So I shut off my stove (had eggs and macaroni boiling) grabbed my test light and multi meter and off we went. I check the battery with the test light and it had juice but the connections were loose. He didn't have any tools and all I brought were those two. After a drive back to my house I loaded a bag with tools and went back. Had to remove the seat and sadddlebags to get the side cover off to find a fuse box. Found it and found a blown main fuse, replaced it and it had power. Then I proceded to look for why. Well it is a suzuki 1400 and the battery sits in front of the swingarm, you have to unbolt a "trap" door and the battery comes out from the underneath. Found that there was a wire nut on a splice to the + terminal with some exposed wire. Tightened the connections and taped up the exposed wire and put everything back together, making sure the extra wire he had put onto the battery leads were covered and made sure they weren't going to rub tire or anything else. The whole ordeal probably took a couple hrs. He had been telling me how hard he had been trying to get someone to look at it, he had no way to take it anywhere.
Here's where the problem starts.. He says what do I owe you (I'm thinking maybe $40) I said what's it worth. He says I'll give you $100. I immediately said NO thats way too much and he says I might need help some other time. So we go to the gas station to get some gas for it and he comes out with a soda and $100 for me. We had been talking about sea foam and I told him I had just got some and he asked if he could get a splash. He brought me home I gave him some sea foam and gave him $20 back and told him that $100 was just too much money. I gave him my # and told him if he needed any help to call me. Now I'm thinking that I really should have given him $40. back and I'm feeling guilty and have no way to get ahold of him :( Am I wrong for feeling this way?