In my area, anyway, there is an introductory locksmithing class put on by the local school district adult (night) school and is taught by a couple of working locksmiths. Good place to start from. I got a good working Framon code cutter for $700. and used it well for several years. Recently sent it to the factory for a refurbishing. Whole thing hasn't cost more than a grand yet. Got a new Ilco semi-auto duplicator too. It's done well for me.
There is some money to be made in specialized locksmithing, i.e. new cars and other fancy stuff, but the initial costs are large.