Yeah, it's a monopoly. They all tacitly agree to a price floor; just like oil companies & gas stations also do; When I worked at a gas station/convenient mart years ago, one of your jobs if you ran a shift was to survey the local competitors' gas prices & adjust yours accordingly. Meaning go up with the highest-price one; but not always to follow the lowest price one, because they might not be prime consideration. Once you got to know the managers of the local competitor stations, you'd just call them up & share the price information; some would be as helpful as to proactively call you in advance of a price change at their store, so you could plan the rest of your shift accordingly. The logic being, if several companies are going to 'compete' for local market share of whatever's being sold, might as well agree on a common price range, lifting the profits of all involved. Shady? Grey area? Dunno, but it was common practice in the Louisville market years ago. The guy who owned the dominant stores in the market-for whose company I worked- was on the board of directors of the other major player in the area, namely Ashland Oil. Now that's SHADY.. but apparently entirely legal.