This mechanic requires players to create deals and alliances with other players in order to advance in the game. When playing either Settlers of Catan or Catan Junior, players have the option of exchanging resources with the market or with other players. While the criteria is set for exchanging with the market, when exchanging with other players, it's up to each player to barter for the best deal they can get. Whoever manages to work out the best deal will usually benefit the most from the exchange.