Bingo. Most people don't realize what parts cost locally (even with volume discounts) vs. online.
One of the things we actively recommend people to supply themselves are headlight buckets, tail-light assemblies, and mirrors. Often the same brand as I can get through a shop-only vender (no public sales) is 2-3 times less than my COST on Amazon. I can buy it as a shop for $100 my cost, list is well above this, maybe 190. Amazon sells the same item for $45. Same deal with radiators, Advance sells a spectra-premium for $175, buy the same thing on ebay from spectra premium for $75.
Of course, the price of amazon is irrelevant, because I can have that part today. Not really apples to apples. Now if you can wait a day; amazon all the way. What the vender is charging is a convenience fee, to the shop, for having it on hand right now, today, ready for delivery. IIRC from a shipping standpoint, the most expensive part of the journey is the last few miles. Just getting the stuff into a warehouse or two across the country isn't hard. And every time is passes through another set of hands, those hands add cost.
Years ago, and probably still today, most manufacturers had a list retail price, and would send out a list of those retail prices to whoever asked for the list.
Legally, the manufacturer can’t force the retailer to sell at the list price, although they can contractually prohibit the retailer from publicly advertising lower prices.
This in some ways made it simple for the consumer.
Most retailers didn’t sell stuff for higher than the list price, with the possible exception of tax and shipping charges.
Many industrial vendors would knock a certain percentage off the list retail price if you were in the trade, or a frequent customer, with the percentage varying depending on how hood a customer, etc.
with the internet, it became easy to cross check prices, and the old list price + discount system went to hell, and many customers realized how much more some retailers were charging than others.
With car parts, if a repair place tells you hourly rate plus parts, unless they have a link to a parts price list, the consumer is just trusting that the place will charge them a “reasonable” price for the parts. If the customer finds out that they paid give times what Amazon is selling a part gor, they feel the repair place is price gouging.
Most people who have paid expenses and hired contractors to repair appliances, or their homes have probably gotten screwed at some point, or a bunch of points in their life, so they may no longer trust contractors or repair people.
Getting charged several times street price for a part just feels like price gouging and getting screwed over by a contractor again, whether it’s the actual case or not.