Time based
These subscriptions are active until their expiration day, regardless of actual use and they offer unlimited race cards. Only one subscription of this type can be active at a time. The subscription will become active right away once the  order is submitted and payment is received.

Count Based
These subscriptions are purchased for a pay-pre-use matter. They provide the subscriber with a limit of race cards and they can be used without time limits. You can have as many active subscriptions of this type; the oldest will be used first until it reaches zero race cards balance until the next one can be used.

You may have only one active subscriptions of either type.

For example:
You can have only one time based subscription but you can purchase multiple count based subscriptions.