A monthly subscription is a billing plan in which a client chooses the amount of credits which will automatically be added to his account at the beginning of each month. A client will be charged automatically each month until he cancels his billing plan. If a client doesn’t have enough funds in the account, the transaction will not be processed, but the billing plan will remain in place until cancelled or replaced. Each purchase extends the validity of all credits by additional 90 days. If not spent, credits are accumulated each month. The amounts of bought credits can vary from 100 to 20000. A monthly subscription has a lower per credit price than a one time buy.