If you have any php/mysql knowledge, you could do this fairly easily. Setup a small database for users to be stored in. Have a field for a "fee" flag or something, then when users pay, update the flag to display that.
Then on each page just have a few lines of auth. code to basically check to see if they have logged in. If they have, they are granted access. If they haven't logged in, it will then prompt them to do so. And if they do not have access, have it display a reason why, such as they have to pay xxx dollars or something.
I haven't lookd into those other scripts, so I don't know if they are free or you need to pay, but if you just needed something quick and free I would do it yourself if you can.
Actually, I'm quite a newbie in programming... I'm trying to find some kind of "ready" (commercial or open source) solution to manage different member areas. I know, that there are a lot of possibilities to build solutions in house - IF I had the knowledge or resources. Unfortunately I don't have