Most of the other gun forums that I frequent require a price to be posted in any "classifieds" posting, and don't allow "auction or make an offer" type postings.
This seems like a reasonable request, as it cuts down on trollers, prevents hard feelings among members who may otherwise get led into a bidding war for an item and prevents wasted space in the listings and much conjecture on the part of forum members within a post.
It's not a big deal, but it does seem to work well most other places, and particularly on a forum that can sometimes get a little heavy on the thread hijacking thing, it might be a good addition to consider here and help keep posts worth reading.
Just my .02 but I'm interested in other opinions.
Mark