OK, I'm assuming that these 100% mark-ups are based on products you are buying in bulk at wholesale prices... right?
If you're buying products at full retail prices (i.e., at CED for a specific job), then a 100% mark-up is absurd. Wouldn't you be a litle upset if you found materials that a plumber charged you $1000 for at Home Depot for $450? I sure would be...
I only add 15% to 25% if I buy materials for a specific job, and then add my time at the supplier (including travel time) to my labor price.
My return customer and referal numbers are very impressive. I attribute this to the fact that I WORK for my money, and don't use every possible excuse to extract every dime possible from my clients.
As for the analogy about the price of a coke and a hot dog from an entertainment or sporting venue, I would rather not keep company with people who do business like they do. Just because they rip people off at every opportunity DOES NOT make it ok in my book.
I'm just sayin...