I think we should make it compulsory to display price in garage sales.
A lot of forums have already implemented this rule like cari forum, even selling/buying apps like carousell is also enforcing this rule.

I see some sellers purposely omitted this displaying price or other particulars so that people will type in "PM me" in the reply to help boost the thread.

This is very unfair to those sellers that provided full details on the first thread vs sellers that purposely not showing couple of details like price, postage, condition etc in hoping buyers will type in "PM me" in the thread to boost their threads.

For me, if you wanted to sell something, just insert your price regardless you are selling online, selling at pasar malam, selling at supermarkets, selling at shopping malls.... all are having price tags, why cant this forum implement it? Why is it so difficult for this forum to enforce it???????

If it is to combat indirect bump, why not suggest every sales thread to be non-reply-able thread?

Simple.