Several stores in the mall sell hooded sweatshirts. each store's sweatshirts reflect the style of that particular store. additionally, some makers use higher-quality cotton than others, which is reflected in the apparel's prices. the government has granted the u. s. postal service the exclusive right to deliver mail. two taxi companies serve most of the market in a big city. consumers don't care which taxi company they take—if they decide it's worth taking a taxi, they flag down the nearest one. there are dozens of pasta producers that sell pasta to hundreds of italian restaurants nationwide. the restaurant owners buy from the cheapest pasta producer available to them.