Help to create SIMPLE payment system.

i would like to suggest something different:

1- create a usergroup that will have privilege access to a specific forum hidden for the other members.
2- create a subscription that will permit to the members to receive the membership to that specific usergroup once paid.
3- create that specific forum for roosters... give permissions only to usergroup created in #1...

... so this is, you do not have to create a whole new system...