There are some homes that are not attached to a share, so there are two options for these homes.
The buyer may purchase the home with membership, paying for the membership/share in full. Your share would pass to the next buyer along with the home, and that buyer would then pay only the established Cooperative Fee rather than rent, just as you did.
If you choose a home not tied with a share, monthly lot rent is charged at market price, and subject to increases tied to the Consumer Price Index each year.