I wouldn’t buy a printer to try and be profitable per say, I would buy one for the things you cant/don’t want to buy. If you can use some 3d modeling software, you can begin to solve problems for almost no money.
Stuff like a vape holder and extended cup holder for my partners car, or a couple little shelf brackets for our IKEA cubes, or replacement closet rod supports. It takes a few minutes in CAD, a couple hours or printing, and 15¢ of plastic, and saves a trip to the store. Making custom, exactly how you want stuff is really nice.
Knick nacks are fun too, but ultimately your house will fill with things you don’t particularly want or use.
I got it on an embedded video for a news site. VPN on of course.