My price is 45.00 an hour plus parts.
Unless the reg is really bad it usually takes an hour and a quarter of labor time to service (complete rebuild) a 1st, 2nd, octo, and swap the o rings on the SPG spool. So 60 bucks labor.
I also do an annual inspection for a flat 35.00 that includes new hose o rings where required, the SPG spool o rings, clean inside the seconds, check, and if necessary, adjust the IP and cracking pressures. Sometimes a reg does not need a full service. If the IP is locking up nicely where it should and only the seconds need a rebuild (new LP seats and o rings), that's all I do.
No need to tear down a reg that is not acting up and is operating as it should. Many regs can go two or even three years between rebuilds depending on the amount of usage and care they get by the owner. Heck I have one pool reg I use that is going on five years that has not needed serviced. It doesn't get used that much and it's a brand that even though I am a factory trained tech I can't get parts for it except on the sly. So it'll get used until it dies and then I'll use it for classroom demos. Maybe even cut it in half to offer a view of the internals for students.
These prices are plus return shipping that is usually around 12 bucks to US and APO addresses. Insurance is extra but highly recommended on return shipping and that varies with the insured amount.