I had a similar thought a while back. I got into making pens. There's a bit of a learning curve and some equipment necessary to get started, but once you get the hang of it, you can turn $20 of materials into $100+, and people with money to blow go nuts for them. I sold 3 pens for $300 to one person not so long ago.
Biggest thing you'll need is a lathe. I got a Wen lathe on amazon for like $150. Get some carbide turning tools for like $40 and you're mostly set.