When is the last time you negotiated prices at the grocery store? Yes, there are places where you can do so, but the prices then get determined almost entirely by the relative skill of the hagglers, rather than the actual value of the merchandise. "Market pricing" is an almost completely unrelated phenomena determined by the intersection of supply and demand curves for commodity-scale trading.
Of course there are other options as well to try to get the best of both worlds - transparent salaries for one: put everybodies salary on their name plaque and you'll get a lot of disgruntled workers if you let Frank' superior haggling skills earn him a substantial pay raise, despite him being the office slacker.
Does that include shopping at another competing store where Item X costs less?