Also... After the year passes and their fee is due again, I want them to be able to just pay the fee without having to buy anything (like a donation).

Membership Customization
1. Create a new product for "Membership" with a set annual price.

2. Add a new field to the customer table in the database for "Membership Expire Date". This is automatically filled in when an order is placed with the membership product in the cart. The date is the order date + 1 year. Display the date on the customer add/edit screen in the control panel and for customers in their account management screen.

3. When a customer is checking out, check their expiration date. If it is a new customer (or an existing customer and the expiration date is past), then a message is displayed that they need to purchase a membership with a link to that product detail page so they can go right to the page, read the details and add it to their shopping cart.

4. Optional: Create an admin function which will send an email to all customers whose membership will expire in a specified date range or send to customers who have expired within the date range.

 

Unfortunately we are booked with other projects and can't help at this time but there may be other developers who can.