We don't have a minimum post count required to sell stuff on the forum but over the past month or two there have been a few users who have been using the forum only to sell stuff. As of today when we (site mods) come across posts from users who are here only to sell stuff we will be deleting the posts and sending a message to the user(s) with the reason why. If your only intent of the forum is to makes sales please either consider:
1) making a donation to the site to offset hosting costs
2)actively participating in the forum via posting
As mentioned in other threads, there is no charge for use of the forum. We just ask that those conducting business either actively participate on the forum (answering questions for new members, etc.) or help offset operating costs via a donation.