Payday 2 - 2,5 keys for open + 9 keys collateral = 11,5 keys
How to opening 4-Pack work - You must not have the game in your steam library, I trade you the 4-pack for a total of 11,5 Keys as collateral, you open the 4-pack which adds 1 copy to your steam library and gives you 3 extra copies to your inventory and you trade me the extra 3 copies back for 9 Keys. For it is necessary you must be able to sell items to Steam Market. If you can't the extra 3 copies will become untradable and i will have to keep your collateral.
Payday 2 - 2,5 keys for open + 9 keys collateral = 11,5 keys
How to opening 4-Pack work - You must not have the game in your steam library, I trade you the 4-pack for a total of 11,5 Keys as collateral, you open the 4-pack which adds 1 copy to your steam library and gives you 3 extra copies to your inventory and you trade me the extra 3 copies back for 9 Keys. For it is necessary you must be able to sell items to Steam Market. If you can't the extra 3 copies will become untradable and i will have to keep your collateral.