I know that this bug work on some OFF servers, so im posting for you to have a try!
Its simmilar to the common shop bugs but it works around a little! Remember the old Shop/Pet bug?! forget it
So how its done?
1. In dual box open two diferent characters
2. Put a shop selling an rare uncommon item like 25kk each.
3. Now on the other char buying the same item for the 50kk, now in order for this to work on OFF servers you will need to have almost the max adena ammount (2,147,483,647) ...
4. The trick is, if you dont have space to collect the adena for the item you will not buy it :P
My advice is to use S/A grade weapons cause they are very expensive in low rates... so you dont need to have all that adena buy for 1,5kkk with a 1kkk in inventory.
I hope you understand this exploit.