i am thinking of something like a box or something that can store a maximum of 11 items(Based from the number of slots in which u can equip your full set, excluding ammunition) in which you can vend based from the total price of all the items stored in the box
example:
in the box i would store all the parts of a costume/armor set worth 1b then sell the box for 1b in my store.
once bought, the buyer only needs to double click the box then the items that were in the box will be transferred to his/her inventory instantly and the box will disappear. Simple as that.
Notes:
*if you hover you mouse on the box it will show you a "menustrip" which contains something like this
(just imagine this is the menu strip and these are the menu list)
Item 1
Item 2
item 3
item 4
item 5
item 6
item 7
(empty)
(empty)
(empty)
(empty)
(empty)
and if you hover your mouse on one of the items in the menu it will show you a preview of the item and it's stats,
i'm suggesting this because i have a job and i really don't have time to go back home and check if somebody whispered
and offered on my set and sometimes when someone whispered and wants to buy my set, i am not present and when i got back home and tried to whisper him/her again he's offline forever. This happens most of the time.