Here's a cool freebie for you! It's a membership plugin for Wordpress, it's not a "lite version" or restricted in anyway. You can download it by clicking the link below (direct download link, no sign ups, etc):
So is there a catch? Not really. It does only work with Zaxaa but since you can use several payment methods there, handle unlimited products (one time, reoccurring and even OTO's) that's no bad thing!
You can sign up for Zaxaa for free and this plugin will even handle drip feeding of content. It's one of the best membership plugins (can also be used to just deliver one time payment products) for Wordpress and it's what I am now using on this site.
Zaxaa has become one of the best sales platforms online today for digital content sellers, its features beat Clickbank, Warriorplus and even JVZoo.