Well u have to consider the fact that everyone (or atleast almost everyone) that sells mana here in jsp have managed to get the mana hack which equals infininte mana.
It's starting to become redicoulusly common even ingame...
Joined a number of games where ppl offer free mana for everyone and then a second after the trade theyve got 30 mil once again.
What u need to find is a poor fellow who dont know about this and did not meet one of these yet. He'll defenitly do it for mana :))