I own an FDM (fused deposition modeling) printer, and I've been kicking around the idea of getting a cheap SLA (stereolithography) printer. The former is the type that takes spools of filament and puts it down in layers like a CNC hot-glue gun. SLA is the type which uses a UV light matrix to cure resin.
You can get a serviceable entry-level printer for about $300 USD. I got an Ender 3 V3 SE back in November, and it's paid for itself several times over between me printing buildings for my layout, printing publicly-available reproduction parts, in addition to high-end puppets and ventriloquist dummies for my son. I've also used it to print my Shell repair garage, phone booth, track supports, and assorted single-lane track pieces.
If you're just printing STL files you downloaded off of the internet, the learning curve isn't very steep at all. The hardest part is making sure your machine is calibrated and that your print bed is level. Assuming the printer is in-order, you just load your STL files into what is called "slicing" software, which automatically breaks the model down into the various layers, plots the tool paths, and places supports and bed adhesion rafts/brims when applicable. For certain models you may want to fiddle with settings, but most of the time I just hit go and take care of minor flaws in post-production.
The real skill applies when you want to design a part from scratch, which is when you'll want good CAD skills. I'm handy enough with a machine, but I need to sit down and develop some strong CAD skills. I've actually got a fellow working on reproduction rail-crossings after I got angry enough about that one guy selling 3D printed reproductions for OEM prices on
Ebay. Once those models are done I'd be glad to give you fellows copies for your own use. Unfortunately, the guy who's designing them for me is reserving the right to sell the STL files (3D models) on something like Cults3d.
There's a fellow who does H0 modeling on Thingiverse and Cults3D by the username Kabrumble whose work I've been using to populate my layout with filler buildings. He does beautiful work, and he says he's willing to take commissions for free. I'll bet if you reached out he'd be may be willing to design reproduction parts; his only caveat is that he reserves the right to post them in his various libraries for people to use free of charge.