is there any type of coarse or class you can take to learn how to service your own regs??? and by "Service" would that be of the first or second stage or both that needs the servicing??? as for parts how can you go about getting parts and i read on many threads that parts are inexpensive??? what is inexpensive 20-30 bucks or would it be more than that or would it be less???
1.) The manufacturers offer courses, but you need to be affiliated with a dive shop (to the best of my knowledge). I think many of us are "self-taught". I bought the books referenced in this thread, got the tools and gauges I needed, bought an old tired regulator off ebay, and rebuilt it. Then another... and another.... It was not difficult; I have some "light" mechanical experience (spun wrenches in the back of my Dad's motorcycle shop as a teenager, worked on ships and tugboats as young man) but do
not consider myself a "real" mechanic.
2.) "Service" (meaning "annual service" usually) involves the 1st and 2nd stage, and anything else attached to the regulator (hoses, gauges, etc.).
3.) Parts can be obtained online for many brands. Some are more difficult (Scubapro and Aqualung), others can be obtained easily (Dive Rite, Zeagle, Mares, etc.).
4.) Prices on "rebuild kits" vary. I've seen ranges of $8 -20 or so per stage as an "average" online; but some rebuild parts that don't get replaced at each annual are sold individually (such as 1st stage diaphragms for some regs, high pressure poppets, etc.). So the cost of rebuilding a 1st stage, 2nd stage and octo could run from about $25 - $60 for the rebuild kits.
Best wishes.