I am not a regular poster but I found the old thread helpful, being a relative newcomer to the hobby the discussion often helped in confirming whether a product was a bargain and a good investment or not. I don't know how funding and hosting of forums work so it may not be possible, however, similar to Banger Blue's suggestion, a section under the 'trade & products zone' or 'modelling zone' titled 'bargains' or similar could be added so it's visible from the home page. Within this section a topic can be created with a title of 'product name, scale and price'. The first post can include where the bargain is and more important information the finder feels is important such as quantities etc. This way someone who is interested can then view the thread and decide whether it's for them or not, and if anybody wishes to add to the bargain or discuss it further they can do below.
I feel that this would give a quick bargain directory where if you are interested you can have a closer look, if not, skip on by to the next.
I am unsure as the whether you can get alerts for new threads or not, if not this was a wasted post and I apologise, and if it will incur excessive hosting costs making it unfeasible, again, I am sorry.
I believe this is a similar set up to the old sales and want a section... and hopefully little to no baby sitting by mods post initial setup.
Jason
Edited to correct 'zone' names