Ah, but keeping track of cost/benefit is a solemn duty in a capitalist economy. The only power you as an individual consumer have against vendors and producers

Ah, but keeping track of cost/benefit is a solemn duty in a capitalist economy. The only power you as an individual consumer have against vendors and producers is the power of choice - the choice to buy which product at what price at which location. No matter whether you have plenty of money or have to turn each currency-unit twice before spending it, if you forget about this you will get pilfered. You will lose track of current market prices for commodities and end up paying through the nose because the vendor in your location has noticed he can increase prices without losing business, thus increasing profits. Others who have less to spend will take their business elsewhere and before you know it you'll have created yourself the groceries-equivalent of an Apple store. So if you happen to see fewer and fewer people swapping products in their baskets because they are not on sale or using coupons or hands of small change or whatnot, take heed and do some comparison shopping.