In the south, there is a grocery chain, known as Food Depot that advertises that their prices are "our cost plus 10% added at the register", which on the surface seems like a very fair deal, as there are other grocery stores and other retail businesses, that advertise that their mark-up is their cost plus 15% or thereabouts, and some of these enterprises charge a membership fee, so a 10% mark-up does sound really, really good.
But, like most things, that sort of sound too good to be true, there are flaws, deliberate deceptions, and the exploitation of consumers that is actually going on within this enterprise. The very first deception is that if your business model is really your cost + 10%, than rather than this 10% being added at the cash register as a separate but distinct charge, it should actually be part of the retail price to begin with. That is to say, rather than marking a given item as $10 and then adding $1 for the 10% mark-up at the cash register, the item should instead be marked as $11 which includes that 10% mark-up. The reason that this is fairer is the fact that the price would now show the complete and full price, with no trickery, whereas an item with a price sticker on it that says $10, makes the real price appear to be $10, despite the "knowing" that there will be a cash register surcharge to it. The showing of the true price also makes it easier for people to consciously price compare between one item that they are use to purchasing elsewhere in comparison to that price at the cost + 10% store, so that when that price does not reflect what it truly costs at the cash register, it is relatively easy to get fooled into believing that you are getting a better deal than you really are, or even whether it's a deal to begin with.
As bad as that is, there is the total hypocrisy of advertising in big bold words that your prices are "our cost plus 10%..." when in very small words, discreetly placed or seldom noticed are the words that most consumers do not read or are unaware of which reads: "Our cost includes freight, stocking fees, and associated expenses." This statement that their costs include freight, stocking fees, and "associated expenses", gives the game up for what it truly is, a sucker game, for most people just simplistically assume that cost would be the equivalency of the invoice amount of the goods so purchased, but in actuality, for Food Depot, costs are really whatever that they want those costs to represent, because "associated expenses", unless specifically broken down to the consumer, can cover or cover-up just about everything.
The exploitation that is used by Food Depot, covers two basic areas, of which the first is, when the true cost is the stated sticker price + 10%, humans have a strong tendency to see the price as shown on the sticker as the price of the good, so this encourages them to believe that what they are buying is cheaper than what it really is, and while Food Depot can talk all day about how they have clearly displayed that the full cost is the sticker price + 10% at the register, if they really cared about being price transparent, and they don't, they would simply change their stickers to actually reflect the total cost which allows consumers to then compare apples to apples. The fact that they don't indicates strongly that Food Depot knows that if they actually disclosed how much their true price is to the consumer that they would not compare well to their competitors, further they know that stickers that fail to reflect that true price makes those goods appear cheaper to the consumer, which benefits their bottom line. Additionally, and this is rather quite pathetic, but the educational system in America is so unequal, that there is a signficant percentage of Americans, that literally do not know how to calculate 10%, don't know what it really represents in cost to them, couldn't calculate it in their head, can't cacluate it with a calculator because they don't know how to use that, and simply kind of know, that an extra 10% represents some additional cost to them, but still believe that whatever that they have purchased is that retail price plus a tiny bit more, never really realizing that the extra 10% is actually a massive markup, specifically designed to trick them