Classified section is usually always at the bottom of the page on forums, so I don't think there is a problem with that.
Filtering the classified section can work, but I think there needs to be some adjustments for it to work properly.
The waiting 1 or 2 days for it to be posted is just way too long. I think if it was changed to a couple or a few hours is needed. Maybe even assign another person access to the classifieds as moderator who can approve or deny new listings.
Once approved. The person needs to be able to edit his or her listing. Make changes or correct errors and to be able to lock the thread so people can see that it is sold before reading everything in the post to find out it's sold.
I've seen some forum that automatically block people from posting unless they have a certain amount of post. So, instead of denying peoples listing or having to keep telling everyone the rules, it's automatically blocked, but also automatically granted access when they do have the right amount of post.
Another good feature would be is if someone has over 300 posts or whatever, they don't have to wait for approval to post in the classifieds.
Another option would be. This is just a idea. But to have a classified membership. Membership cost $2 per year to be able to post in the classified section. This is to keep random anonymous people from signing up or doing transactions with people. It's makes sure they have a current payment address on file. That way, if something ever happens, you have a record of who they are. Who wants to rip someone off if you have your payment information on file. Only can be used for bad transactions only if needed. Some people might feel safer this way to, I know I would. I'm sure there will be some anti government tinfoil hat people that don't approve, but not everyone can be happy right?
I've seen one of the best local gun forums go down in flames because they started charging people way too much to use the classified section, not the site is junk. It's was like $35 for 3 or 6 month. So not worth it for anyone who just post a $10 item once or twice a year. So, keep the membership low, just to get that info can help out in many different ways.
These are just ideas I thought I would share with you. The classified section will work without these things I suggested, but I thought they where worth mentioning.
I have close to 200 online sales on forums and Craigslist, so I do have some private party sales experience. Selling live fish, aquatic plants, guns, cars, automotive parts, collectible items, electronics and many other things.