This would be a difficult question to answer for a few reasons.
1. It would depend on which sever you are playing.
2. At different time of the day, the average cost for a winning trade bid varies on a particular item on a particular server.
3. When some event are on, some player change ship then change back so before and after winning bid price will go up.
There may also be other factor to take into consideration. Like how much credit you have and how quickly you want it.
I have bought elite ships on trade for 1 cred, but was very lucky and in no hurry to get the ship. However I have heard of 30mil+ bids being lost on a goli and that was not on a server with a high number of player.
The best advice is to ask in you server company chat. You should be able to find someone that will give you some idea.
Hope this helps
Last edited by -pacman2- : 20.06.2011 at 20:07.