BTW, they wouldn't be paying Coke or Pepsi ...
Coke, Pepsi, and Others make drinks, package them, and sell them to a distributor. The distributor is able to pick and choose which to carry. The distributor then sells the products to the retailer. The retailer, however, may have a contract with Coca-Cola or Pepsi which prevents him from selling the competition's drinks. However, since the clause is usually specific only to Coca-Cola or Pepsi drinks, the retailer can usually bring in drinks from 3rd party companies, such as Cadbury-Schweppes, without violation.