Can I just purchase a membership to a plugin?

Dear WPMU

I bought in a deal your plugin "Membership" though I would love the fantastic savings that are on the membership to your site.

Though, I feel that the loads of plugins are not really appealing to me, but one, the "Membership" plugin.

I would just write in and ask if it is in any way possible to buy either an subscription to the plugin or buy a lifetime-updates plan.

If possible please get back to me.

Best Regards
Lucas Dechow