Re: Little Auto Mechanic experience...
I'm surprised that the O.P. is surprised! This stuff is as old as service shops. (Auto, HVAC, Plumbing, etc.)
Ever had an estimate from a basement repair guy? When he's finished his story about the impending collapse of your house, you'll try to get the work scheduled for tonight!
I recently posted about a Toyota dealer (Wilde Toyota, Milwaukee - largest in Wisconsin) doing this to a female friend of mine on the 3/36 inspection - worked it up to over $500 when the needed work was about $260.
Several years ago, I caught a Pennzoil oil change shop a quarter mile from this Toyota dealer using oil from prior oil changes. And another one in the same vicinity offering to replace "burned out marker lamps" that actually still worked just fine.
This is a very common embodiment of one of the most prominent American characteristics: "GREED".
As mentioned above, the O.P. needs to find a shop that can be trusted and stick with it.