I get how a search option could be difficult because the speed at which things sell. I think the most frustrating thing is finally seeing what you need, and it takes 20 seconds to load to an empty trade market. Btw: this new update has slowed down the loading time. I can barely buy anything. So, I'm barely playing.
I think if I clicked on "nails" and someone bought the nails before me, automatically give me all nails to choose from, from other sellers, in a global trade hq window. Instead of the seller's rack without the item.
If I want to see what else this seller has, I could just close the HQ window.