Law of one price The law of one price states that the price of goods of identical quality should be the same in different markets. --Transportation costs must be zero. --No barriers to trade. 袋 Market forces tend to push prices toward equality. Arbitrage:buy the good in the less expensive country and sell the good in the more expensive country.Law of one price The law of one price states that the price of goods of identical quality should be the same in different markets. --Transportation costs must be zero. --No barriers to trade. Market forces tend to push prices toward equality. Arbitrage: buy the good in the less expensive country and sell the good in the more expensive country