Im interested in the communities help here
Hm, difficult sometimes its easier to buy piece by piece. The only valued items is amulet and armor, other pieces (orb, mask, belt) is all over and is easy to get.
Of course there is perfect versions (2/2/2 orb, 15mf belt) and so, but not that important.
If you wanna wait and no rush - I think you can get the amu for 1 ist. But easy you can get for 2 ist, but I wouldn’t pay that.
Armor is much cheaper if you using more than this site, people still think it’s with an ohm like in the beginning of this game.
It’s worth maximum a vex, maybe only 3 ists. I’ve seen people selling for that.
Hoped that help you a bit 
Yeah Tals armor i still see people batting prices back and forth on so thats up to the hagglers hehe
Tals ammy seems like an ist is the standard now. I’ve seen quite a few trades go for that with both sides seeming pleased with it.
Yes, as mentioned if your patient then you can have amu for ist. 
I wouldn’t pay ohm for full set, I would say you can get it cheaper piece by piece
Full set should be vex ist at the most, other than that is too much 