-Look for someone who is selling an enchant and suppling the mats
-Trade them, put your item in (will not be traded) and put in the amount of gold they want for the ench
-When they put the enchant on your item deleted the money before they press trade and then trade.
You have one enchant and they have no gold
Timing is everything, so If they press trade before you can delete to gold, close trade and start over.