I would probably participate in these threads if prices were listed, but I currently don’t. (Edit: Scratch that, I sort of just did)
As of right now, I suppose it’s the seller’s choice as to whether or not they want to list the price. If they’re serious about selling, then it behooves them to list a price as an invitation to at least negotiate. But if they don’t, then they probably aren’t going to get many people to bite. Then again, I’m certainly not speaking from experience as a seller. I can only speak as a buyer. But I’d think it’s in a seller’s own best interest to list a price, even if it’s on the high side.
To be honest, however, the mods and I have generally taken the position to avoid being heavy handed when it comes to rules and moderation. We take the term “moderate” literally when it comes to pushing the direction of things or clamping down. We’ll do it when we need to, and so far, there hasn’t been much to moderate.
So in this case, if there’s a huge demand for it, we’ll probably discuss it. But generally, we like it when the community comes up with its own etiquette. So far it’s worked out well (in most instances). And if someone lists something with no price, I’d prefer if we didn’t have to flag them down or anything.
But if a ton of people start listing items for sale without prices and the section becomes useless for buyers, then we’ll address that. Or if another mod has more of a desire to enforce such a rule because they think it’s necessary, then I’d defer to their decision. By all means, this isn’t set in stone and if you think it’s the wrong approach, let me know.