In Ceriah, "real" money - that is, money your characters use to buy food, clothes, and fancy cars - is separate than what they use to gain access to TMs, evolution stones, and other Pokemon-related items. Access to the league store is restricted to trainers and using their resources costs a special kind of currency known as credits. Credits are awarded whenever a trainer defeats a gym leader for the first time, places in a tournament, or battles in an official league arena only in matches set up by the facility itself. The number of credits a trainer has is recorded in the league's database (it is not an actual physical currency) and can be accessed at the league store by showing proper photo id. Credits are normally non-transferable.
Participating in random matches at official league facilities grants credits equal to 50 + double the level of each participating Pokemon. For example, battling with a team of Pokemon levels 13, 14, and 15 would grant 50 + 26 + 28 + 30 = 134 credits. Winning the match doubles the prize money. In the previous example winning would have granted 268 credits.
On the subject of real money, you should take some time to consider how your trainer is financed. Pokemon Centers do not give trainers free lodging or food and if they have a car they need money for gas. Being a Pokemon Trainer by profession isn't a viable source of income until you're strong enough to place in tournaments, either winning prize money or receiving a sponsorship.