In the olden times, students started off with a micrometer, a file, and a block of steel, and had to make a perfect 1" cube as part of their studies in the first year.

You can start really cheap with just basic hand tools, there are lots of bench size machine tools, like mills and lathes, that come onto the market as their owners age out.

Know that if you do get a mill, lathe, CNC, etc... fixtures, jigs and cutting tools will cost at least as much as the tool itself. All the things like vices, t-slot hold down kits, various milling and lathe bits add up fast.