If you are using premium membership with one time purchase option then you probably want to allow your users to be able to renew their membership.
Renewal payment buttons are exactly the same as the standard membership payment buttons. When logged-in members pay for the membership level, their account access gets extended.
Do the following to put a renewal system in place:
Step 1) Go to the following settings interface in simple membership plugin:
Settings -> Advanced Settings
Step 2) Enable the “Enable Expired Account Login” option and save the settings.
This option will allow the users to log into the system even if their account has expired (or set to inactive). They won’t be able to view any protected or restricted content. You are just allowing them to log into the system, so the system can recognize them and apply the payment to their profile.
Step 3) Create a WordPress page called something like “Membership Renewal”.
Step 4) Add your renewal payment buttons in this newly created page. You can create the renewal payment buttons exactly the same way you created the normal membership payment buttons. You can even re-use the existing payment buttons (if you want to).
You should use the payment button shortcodes from this plugin to create the renewal buttons.
Step 5) Protect/hide this “Membership Renewal” page so members are required to log into the site before making the payment. The plugin can easily apply the payment to a member’s profile when the member is logged into the site.
Step 6) Specify the URL of this newly created page in the following settings field of the plugin and save the settings:
Settings -> Advanced Settings -> Membership Renewal URL
Now, your existing members can log into the site, go to the renewal page and pay for it. When a logged-in user makes a payment, it will apply the payment to their exiting account.
Expired members of your site will see a message like the following when they try to access a protected post/page. Clicking on the renew link will take them to the renewal page of your site.