About borrowing from Guild Members, it's not strange at all. Someone bought something from me for 300K, which he al borrowed. Now he payed all that back, and borrowed another 650K to buy more from me. He even payed upfront (he bought Pre-Searing items with Post-Searing gold, and yes, I gave him his items

He's even on these forums). So saying people that borrow would never give it back, think again, many people would.
A Plasma Sword is worth nothing, it's a collector's item from Dragon's Gullet. Just like the Fiery Flame Spitter, it sells for insane ammounts every once in a while, which is lame, since both are only worth a couple of lowsy items to the collector.
700 ectos for that 15% unconditional Dwarven Axe is a scam. If it wasn't customized by the owner, it diserves 2000 ecto offers. There's most likely only one 15% unconditional axe, and it's a Dwarven Axe too, where you'd pay ~2 Million for if you'd ever find a 15>50 one again, which has been found like 5 times. And yes, this is the most expensive item in game. Others are:
Crystalline Swords, 15>50, req. 7/8
Dwarven Axe, 15>50, req. 8/9
15% Fiery Flame Spiter (heard it sold for 800 ectos this week, but not too sure if it's true or not)
15% unconditional items, max damae, any req.
-20 Health Axe (I doubt anyone in the world will sell this axe though, I'd pay a couple of 100 ectos for it now right away. Too bad I didn't take te 800K offer when I saw someone selling it in LA)
Can't think of much else. I'd pay pretty much for that 10% unconditional Armor Penatration staff myself (when I last had it, it worked on Flare too iirc) which got nerfed a while back, but I doubt I'll find it.
And getting 20 Million isn't always ebayed, it's very possible.. Stop telling them they're ebayers, since that's just a conclusion you made because you can't get that much money.