should I

[Molgorain]

If the sale-section would be PM-only, we might need a bigger Inbox for PM.
When a product is sold, the topic-starter should add the text [SOLD], and then a mod can delete it.

A feedback-system would be great. On a swedish forum, we have a small number after our name. Where you could see how many have left some feedback about the user.

It splitted into three groups.

Feedback last month
Feedback last 6 month
Feedback last 12 month

You can leave three different "grades", Positive, Neutral, Negative, ofc with a comment. People can also see who you have been giving feedback.