Ok thanks for the info. Looks like multisite is what I would need to do what I want.
Looking at the multisite info, I can "share" users between sites.
1. In a multisite scenario with shared users (i.e. I would only enable registration/add new user on the main site), how would a user's listings between sites integrate? eg. Will the user see all his listings across the sites in his user profile? Will a visitor be able to view all the listings across sites for a particular user?
(this is assuming the user has listings in different states/sites).
2. Regarding importing categories for each site, is it possible to have the child sites inherit the classipress categories of the main site? updating dynamically if possible.
3. If I set a state as my top level region, do I have to go in and add all the cities? or does it automatically pull in all the city data?
4. If I purchase classipress initailly, and then decide to upgrade to the $249 level, is there an option to just pay the difference?
Thank you