Okay. The only reason why I suggested a free build was because labour is apparently the only part of their servies that they can affect the price of; manufacturers set prices below which shops can't sell parts or they can't sell parts for less than what it costs to run the place.
The reason why I posted this question is because I didn't want to be rude. I would never walk into a shop, regardless of how much money I had spent there, and suggest that I deserve a discount. I work in retail and frequently have people do that exact thing - it's dirty and classless.
"Should an employer cut my wages because someone else will work for less?"
What? Show how that is parallel to what I was suggesting.
I think it's great that you have the money to buy pay more than you have to for parts, but for me it would take several more months to save that kind of money.
I find it funny that you would rather, your shop lose more money from me not buying all my parts from the shop, than get a free build. Mechanics get paid by the hour, not on commission, right? So why would you be more upset if the build you did was "free" or not?