Piggybacking on what alwhite00 said; doing it yourself will give you an idea of cost vs effort.
I do my own tires now and changed them on my Voyager several times. There is a lot of work that goes into getting the rear wheel off the bike; even with the shortcut to the manual that Peg mentioned.
For a dealer; that is NOT a bad price at all.
You might be able to find an independent shop to do it cheaper; but unless you know of a good shop; you're dealing with an unknown.
I used an independent for my first tire change on the Voyager. It took about 4 hours longer than quoted and they beat up my rims.
Made up my mind after that to do them myself. I bought a no-mar tire changer and it's paid for itself many times over now.
It's a real pain in the @ss.
But I KNOW the nuts & bolts are torqued correctly, the drive shafts are lubed correctly, the brake assemblies are handled and re-installed correctly.
Anyway, the business owner has to pay for the tech's time, his shop space, tools, and utilities before he starts taking his profit.
The degree of 'pain in the @ss
' a job is; will relate directly to how much he can/will take.
Too high and more people will do like me and do it themselves, to low and they're leaving money on the table.
I trusted the shop & technician; $260 would be a pinch but not a gouge.
To clarify though. I AM CHEAP.