I agree with making a separate adoption forum from the for sale forum. Mostly for the reason that it will help those trying to re-home a snake to not get lost in the other ads.
I don't agree with any of the ideas that have been posted so far about limiting the ability to post in the for sale section. While I agree it is sort of an abuse of the forum to post a for sale ad when you've never posted anything else, unfortunately none of the ideas suggested would stop a scammer. The best one is probably the idea of requiring someone to have been a member for a certain amount of time before posting a for sale ad. However, that only slows down the scammer; it doesn't stop them. And it unfortunately also slows down many legitimate people who might want to post a for sale ad. I think we lose more than we gain.
Robin and a few others made very good points about the buyer needing to be sure they know and trust who they are buying from. It is not the job of bp.net to protect foolish people from getting scammed. And the better and/or more determined scam artists who will catch a few of those who aren't so foolish will manage to slip through any rules that could be written, so we can't stop them before they scam anyone. Once they scam a few people and become known, they will be dealt with as we have already seen.
One idea that might make it slightly easier for buyers to do their homework is to add a new sort of rep points to bp.net. Let's say we call them vendor points. The idea would be you only give a person a positive vendor point if you have made a purchase from them and are happy with the results, similar to the way it is done on ebay. By using a similar system to the one we have for regular rep points, abuse of this system would be difficult because a scammer couldn't just register multiple times and give themselves rep. It doesn't count until the person has been around a while and earned some rep themselves.
I have no idea how hard this would be for the administration to set up, and it might be more hassle than it is worth. The bottom line would still be that the buyer needs to do their research, just like it is for each and every purchase a person makes, online or otherwise, reptile related or not.
I almost forgot one other thing I wanted to say. To enforce the rules that currently exist, I do not believe we need to prevent newcomers to the site from posting for sale ads. Who cares if someone's first post is a for sale ad if they then go on to become a "contributing member"? I probably wouldn't trust them to make a purchase, but I don't mind them posting the ad. However, if it becomes habitual that someone posts only for sale ads, or more of those than other posts, that might be a reason for some sort of probation or eventually being banned.