Have the right tools for the job
These are the tools I think every tinkerer should have in their setup. You can get more expensive versions of each of these tools, but these are the ones I recommend.
Everyone needs a good soldering kit, I have a $120 hakko soldering station, but I end up using my cheap portable iron 90% of the time.
Hot Glue Gun
Hot glue is the new duct tape. Almost every project that I finish has some hot glue on it.
The difference between nice wire cutters and cheap ones is night and day. Spend $5 and get a pair that will last.
Dupont Wire Crimpers
Make your projects look great with a set of Dupont wire crimpers, stop using generic 1 wire jumpers and make grouped jumpers specifically for your projects.
A multimeter allows you to easily troubleshoot your projects when something isn’t working.
A 3d printer is a modern day Maker’s most powerful tool. The first printer I ever used was a $3000 MakerBot Replicator 2, and 7 years later it’s still printing decently, but for $240 an Ender 3 produces similar if not better results with more flexibility of materials.