That a question like: How long is a road!
Obviously, 3D printers come in all price ranges from a couple hundred to tens of thousands of dollars! Pricing is based in the size of model, the media used to print, and the printing technology.
How long it takes to learn to program is again a question only you can really evaluate. It will be at least how long it takes you to learn to do 3D design drawings, again a number nobody can really state as it depend on the individual.
You can use existing 3D designs much faster, but even learning the in's and out's of a specific 3D printer is a vary variable number.