I just wondered if there was any way of making a section on my forum where you have to have a minimum post count before you can post in that section,

if you understand what i mean?

Here's my forum : http://ukfishingforums.darkbb.com/index.htm?sid=beebfb3226b7081958bf3946e470aede

and what i want to make happen is have my members have a minimum post count of 10 before you can post in the buy and sell section.

You can make an auto group and then set the permissions for the section.