Well first you can check various things to find out the prices. Nera castle chan 3, various selling forums. But ill say the biggest determinate of all that gear is the person selling it. Some people jack the price of high eva stuff. 20 eva is high so that will be more expense, i think before i saw something with 20 eva for like 10 bil.
Also its just my opinion but rham you sound like you dislike clise in that post by mentioning in game things that have nothing to do with this matter.