Often they don't, 'though gas prices are a special case since they affect every retailer, and their margins are often razor thin as they are.
But consider Kindle vs paperback prices on Amazon for the same book. If costs were the most important thing in setting prices, the former would never be more expensive than the latter; but we see it often is, because demand sets the price, not cost.
But consider Kindle vs paperback prices on Amazon for the same book. If costs were the most important thing in setting prices, the former would never be more expensive than the latter; but we see it often is, because demand sets the price, not cost.