the motor cost $193 and the starter cost $305
I run into this sort of thing all the time in residential work.
Example #1: Home-owner buys a set of lights at the DIY store for ¬£9.95 and then queries why it's going to cost an additional ¬£25 in materials alone to install them properly.
Example #2: Owner buys a ¬£49.99 electric shower for his bathroom and nearly has a fit when quoted ¬£250+ to add the necessary branch circuit as there's no spare capacity in the panel.
Best one on a commercial job was the pub owner who asked for a quoye to install an exhaust fan in his kitchen. It involved fitting a heavy-duty 12-inch fan, knocking through about a 10-inch brick wall and making good, as well as the wiring. IIRC, the overall quote including the builder I would have subbed the brickwork out to came to about ¬£400. The guy was thinking of those cheap little bathroom fans that retail for about ¬£10 and thought that anything over ¬£100 for the whole job was outrageous.