Erm, this is not related to the game but more to this site, or well not the site but the people in it. There's one problem about TGs and trade in general that bother me a lot ; It's that labelling trades as "ty" is still allowed. Many players use it to hide low price transactions (I assume about half of my tys as straight scam), and others I don't even understand why they do it.
Median already doesn't have that many trades, if half of the items are hidden behind ty, it become harder to do price checks, sometimes impossible, even for common items. And because you struggle to price check, you end up selling underpriced, that will get of course labbeled as a ty. Theses trades for exemple only are items, a 95% mf lilith, a quov tsin talisman, a seal of the nephalem king ; etc. What are they all doing?

That's a personal exemple, but 95% of the time just watching the latest transaction can make you see the problem. It has way more than half tys if we remove auctions.
Here I sell the same charm ; The Sleep with fire,cold, light res to 3 different persons ; notice the difference in information.

In concept, making an auction should be innatractive ; the seller has a fee, and the buyer has to wait up to a few hours to get his item, and have to sweat to get it. Yet it become the preffered way to sell things, because you're sure to get a fair price, and the item will be properly listed. It's very weird really.
Proposed first step solution : The seller can also label his transactions.