Besides selling drugs I'm not sure there's another way to make money faster than resale...at least that's how it has worked for me. The biggest trick with resale is knowing exactly what you're looking at. The think the best thing to do is get super educated on a particular item(s) or area(s) and focus on that. There was a little while where I was flipping anything I could find that I thought was a cheap enough to make a profit on, which works but then I realized I could make a lot more $/hr focusing in on a couple areas/items in particular. I took a couple welding courses years ago, like you mention, and while you can make money doing welding on the side I can make a lot more $ buying broken metal stuff, fixing/welding it, sanding, painting it and reselling than I ever would if I spent the same amount of time just welding small projects for people here and there. You gotta have room to do this stuff too, especially if you're selling cars and motorcycles like you say. If you have the room to safely hold/work on 3-5 cars, 2-10 motorcycles at a time you can really make a lot with consistent money coming in, instead of just selling 1 item at a time and moving to the next.