need help on selling materials...

I don't think i quiet understand this new selling interface...
First of all: what does that "Last sale" means? I know it means "last sale" lol, but.. let's say, someone just sold a fur square to a trader for 100 gold. Will the trader "last sale" says 100 gold?
First screenshot: the glob has a value of 100g, but you have to buy it for 12k
Second screenshot: I can sell the Lump for like 149 gold, but when i gotta buy it, it costs me less then 149...
Third screenshot
Fourth screenshot: the value of a fur square is like 10 gold? :s
Fifth screenshot: I got 13 Fur Squares atm, and I can sell 10 of them for 1k, but if i want to buy them (10) i gotta pay 4k...


Please, can someone explain this to me? If been trying to find this out for like days now lol

when the prices are insanely low to sell hold onto the item and try to check often for a price spike to sell

examples

leather squares are going now for about 18 gold each to sell them

and furs were only 15

i sold a bunch (over 20) leather squares a few days ago at 200 EACK
same for furs at 453 EACH

you can waste time trying to sell to a real person if you want or simply keep checking for a good time to sell

of course the price may not go up so who knows

With the new patch, it seems the price will never go up. I think that an undocumented effect of the patch is that the NPC buy and sell prices are almost always orders of magnitude apart. This is why the NPC traders are always out of ecto and shards now.

then why was i able to unload a dozen leather squares a few days ago (after the patch) for 200 EACH (i just got rid of 57 more at 177 EACH a few minutes ago)

and furs 11@ 453 at the same time