Gasoline is pretty much a fungible commodity. Almost all gas stations sell two or three of the standard grades of gasoline, and almost nobody believes advertisements that claim that one gas station's brand of gasoline is better than another's.
In part as a result of that, gas stations operate in something very closely approximating perfect competition, in which market forces drive competitors to all sell the product as a market price that has a quite thin margin. There are differences based mostly upon locality, but almost all competitors follow the strategy of maximizing sales by selling at the prevailing market price.
But, the law does not fix gasoline prices and there are a few gas stations that zag when everyone else zigs and charge far more than the going market rate for gasoline.
I am aware of at least two such stations in Denver.
The worst offender by far is the Shop Fast at 6504 E. Alameda Avenue at the intersection of Alameda and Monaco. This gas station generally charges thirty to forty cents per gallon more for gasoline than the 7-11 gas station three blocks away at Leetsdale and Monaco selling precisely the same product.
Moreover, it isn't as it the Shop Fast is offering a superior customer experience. Its pumps are primitive early 1980s versions that can't take your payments at the pump and haven't been upgraded for decades. When you go in to pay, the convenience store is dilapidated, dirty, disheveled, understocked with lots of empty shelf space, and has a poor selection of products to buy. The attendant on the couple of times that I have been there, has always been surly and rude.
The Conoco at Speer and Pennsylvania Avenue has a tidy and ordinary convenience store and modern gas pumps, but does engage in price gouging, typically charging twenty to thirty cents per gallon more than nearby stations such as the two gas stations at the intersection of Alameda Boulevard and Downing Street.
While government price fixing can create all sorts of problems, it is hard to think that the price gouging practices of these gas stations, which prey on people who are inattentive (a strategy that usually works when buying gas since so few gas stations charge and above market price and it is hard to keep track of weekly variations in gasoline prices that fluctuate rapidly), or aren't away of nearby, much less costly alternatives because they are in an unfamiliar neighborhood, promote any legitimate virtues.