Ubercart or E-commerce

Hello,

I´m developing a job portal in Drupal 6, I have already developed almost all funcionality, but now I´m stuck in the payment requirement because is the first time im working with it

For that reason, I would like to ask about what should I use, Ubercart or E-Commerce or maybe an other alternative to solve:

1est. One user have to pay for create content (for publish a job)

2nd. One user have to pay for acess content (for access other user profiles)

for the 1est issue, I have think about payment for memebership, assign a role to a user after paying, so with that role this user will have permission to create content, the problem is how to specify when and how a user will leave a role depending on how many job publications has bought, if he pay for publish just one job after it, he will have to leave the role. Maybe I can do it with rules

for the 2nd issue,
I have thibk about take profiles like products, so the user can buy adding to the cart the number of access they are interesting on, and after pay the user will have access to all this profiles.

greetings!!!