The Flexi class system is a subscription based service so this depends on how many credits you purchase. You can check out the costs of different subscriptions on the table above but the cheapest program would cost 56USD (or your currency equivalent) and this will get you 1 group per week for 4 weeks (14USD per class). The more classes you commit to, the cheaper the classes become. Some packages offer less than 7USD per class, absolute bargain!