Taking the Rear Wheel Off my '81 750 LTD

Let's hope you got a good tire. Some places charge a lot for the installation - $75 or so plus all of the nitpicky type of add ons, such as tire disposal, etc; in particular I'd guess the dealers charge the most. Look at the bill to see what the individual costs are. Depending upon the tire & city and w a little effort/knowledge, you might've gotten it done for $25-$75 less. Just a guess.

I replaced both tires on my bike with new Dunlaps for around $200 including them installing and balancing. I took the wheels off and took the wheels to them since they said the cost would be double if I just took them the bike.

Thanks - maybe it wasn't as bad as I thought.
For the future - if I were to get a tire online - can't I just bring the wheel and tire to a gas station and have them mount the tire?