This topic is somewhat of a sore-spot/tender territory here on Piano World; especially over on the technician’s forum. Not sure why, but I have my suspicions. Some are understanding and helpful and others are critical of the idea from the start.
I’m in the process of learning to tune and service my own pianos. I recognize my skills are at the early stages of the learning curve and I need a lot more experience; but my tunings still sound a lot better than some out-of-tune pianos I’ve played at some piano dealer showrooms, and better than most YouTube piano music videos I listen to.
That said, it is not at all easy. Give it a try and you will see what I’m talking about.
Just a bit of advice from one DIYer to another… buy a good tuning hammer, and not one of the cheap apprentice ones. Read up on the subject as much as you can. Learn the terminology and the jargon. Get a decent tuning program or electronic tuner and learn how to use it. Then, practice, practice, practice, and practice some more.
Oh yea, I forgot to weigh in on your original questions… like BDB said, $500 is not a bad place to start, but might get by with $300 or so initially. As far as the time element involved, it took me 8 hours to tune my piano for the first time… now, I’m down to about 2+ hours if all I do is tune. Regulation and voicing?... well, how much time ya got?
One of the benefits of tuning your own piano is that you only have yourself to please…