The hidden extra cost of sales tax and tip when you go to pay in America feels very much like a scam. I don't understand why the cost is not just exactly as advertised like everywhere else.
I was even more surprised to find out that delivery services don't pay tip to drivers on top of the agreed upon rate for their service. Instead the rate they're are paid is adjusted as per the tip provided so that the total amount of money they make remains the same per delivery.