ok this is fairly easy to pull off, yet very effective.
(might not work with cautious people)
(also, do it on a noob, unless you want a reputation of being a scammer)
things you need:
1 darkwizard
x darkrobe (x=the amount of times you want to pull this scam)
patience
i just pulled this scam about 4 hours ago so, tested and worked
on my server, a darkwizard cost as much as a db.
1.first, you go spam in market that you're selling a darkwizard for 5kk less then normal price( in my case 40kk)
2.then when someone trades with you, put in the darkwizard, but cancel when they agree with the trade
3.quickly trade again with them, but this time put in the darkrobe and also agree.
there you have it, you just traded in something worth 2kk for 40kk
like i said: tested with succes