Charge by Advert Type
I think Classipress would be more suitable to many users if we had the choice of charging by advert type: example.
Create three forms - Free Listing, Premium Listing, Featured Listing
Then charge by the FORM instead of a Category or Flat Price.
I have suggested this for a future release, if you agree, please go here :Ability to Charge by Advert Type
and vote for it, the more votes we get, the more likely it is to be considered.