I see on the buying page that ad listings are sorted by price, lowest at the top, highest at the bottom. This is good in some situations. I wish this applied to the selling page as well, highest price at the top, lowest at the bottom.
Although it would be best to have other options for sorting too…
There should at least be options to sort by reputation, price, and user activity (say someone wants a really quick trade, they might look for the most recently active seller/buyer).