I learned to machine mostly on my own. I had a lathe in high school which was used only to true commutators for electric motors. In high school I learned how to program G code on my own with a small CNC lathe that was the size of a sherline lathe.
There are plenty of books and resources to learn how to use a lathe or a mill. Yeah, it's nice having someone around, but when I bought my mill I just took it easy and figured it out. Not an expert, but can make parts.
In your price range, I wouldn't buy the mill. It will have really no other uses other than doing 80% lowers. Not worth it. Either step up to a larger machine (double your money just for the machine) or go with AK tooling. The AK tools will also be useful for other things whereas the mini mill will really not be.