We don't post a number here because what a Belvedere Park job costs depends on what's behind the drywall - whether the header needs backing, whether the existing door is heavy enough to need a stronger opener, and which drive type you want. What we can tell you is that the area's median household income sits at $68,900, and most of the openers we install for homes at that budget are chain or belt-drive units sized to a standard single or double door, not the heavier-duty commercial-style motors.
If your garage was never wired for an opener - some of the 1961-built houses here weren't - expect an electrician's-level conversation about running power to the garage before installation day, not during it. That's not a cost we can quote blind, and we won't pretend otherwise.