@giffenk the hog regs were certainly the case when you could get a D1/Classic for $200 and couldn't DIY service for whatever reason. Those are no longer available.
The Deep6 DGX series is basically the same regulator and is $250 for the set. Parts to service that are $50. If you have to pay someone to do it, I've seen it as low as $60, or as high as $105 to service. I know that those regs can easily go 5 years between service so you may decide that at the end of the day you can sell those regs for $100 needing service, and pay $0-$50 to have a brand new regulator. The guy that bought the reg for $100 is probably going to DIY and he saved $100 on the cost of the reg so everyone is happy.