@Xela, I'm sure you are kidding, but the price would not likely be $10. The liability waiver, indemnification list and certification of techs is already keeping the cost down as it (hopefully) is deterring frivolous law suits.
It takes me about 20 minutes to mount a pair of new skis and test them; I measure twice, drill once. At $10 per M&T, I'd be generating $30 an hour (best circumstances). That doesn't leave the shop owner much room for profit. For remounts you can easily add 10 minutes just for removal of the bindings and filling the old holes. Then you have to determine where the binding can be remounted without conflicting with old holes. Plates are becoming a bit of an issue these days as some are 'hostage' requiring you to use the binding that the plate was designed for. This makes the mounting trivial as they are pre-drilled for pre-determined mounting points BUT if someone brings in a ski with a hostage plate and a binding that isn't compatible there is a lot of hand-holding explaining why they need XYZ binding for XYZ plate. Then there are the problems of some plates now incorporating metal sections and of course the inevitable plate mounting screws; both these scenarios require careful planning to make sure the binding gets mounted appropriately without conflicting with the plate's screws.
So for as easy as mounting bindings seems to be, for mounts other than on brand new skis, there are lots of things that can complicate it.