It depends.
Memberwing membership plugin for example can be applied to any theme.
And in fact it will make your membership site well optimized for search engines. So even premium posts and pages will include free teasers for ranking and indexing.
Gleb
Thanks I just checked memberwing, it rather expensive though, suppose you haven’t one there for in around the $100 mark..?
Byron2k12, most of the membership “plugins” will work with any theme.
Paid Memberships Pro is available here in the WP repository and works well with most themes. If not, it’s usually a quick CSS fix to get things to look well on your site.
http://wordpress.org/extend/plugins/paid-memberships-pro/
The plugin is completely free. You can get support at http://www.paidmembershipspro.com
Good luck.
Hey there!
You can also try http://premium.wpmudev.org/project/membership/
There is even a Free Version to try on 🙂
If you decide to purchase then you get the guarantee of updates and support 🙂
Best of Luck!