There is no working and public Trade Hack. Maybe your friend had a version which was just a fake. Don't believe if someone wants to give you such a hack.
TRADEHACK 05/21/2013 - Metin2 PServer Guides & Strategies - 19 Replies Guten Tag liebe PvPERS, habt ihr vlt einen Tradehack? :o
der auf P server auch funktioniert? :))