What is the difference between a membership and a package?
The primary difference between a membership and a package is that one is recurring and the other isn't.
When buying a package you pay a once-off fee and then the package itself either runs out or expires.
A membership on the other hand is an auto-renewing payment and begins immediately after purchase.
Your fitness provider might offer better rates for memberships as it is easier and faster for them and their accounts. For you as a client its also easier and faster as you don't have to enter your card details every week/month!