After using Classibase v 1.4.4 and 1.4.5, I would like to propose a few ideas for improvement of the script:
1- Paid membership: The principle would be allow paid membership to the site granting for example x number of ads to be premium in exchange of a fixed or monthly fee. The benefit would be to have a better and more flexible pricing scheme for regular users.
2- Referals: there idea would be to allow users to send links to friends, family and relatives to boost site audience and grant referring users with benefits like premium ads, etc…
3- Access restricted to members only: the idea would be to only allow registered members to see ads posted by other members on the site