while you are playing on the Verruckt map, you will need to have 2 bouncing betties and enough money to buy a perk and another weapon.

So what you do is put one betty wherever, but when you have one betty left, go up to a perk machine and put the betty down in front of the perk machine and immediately press "X" to buy the perk.

When you are done drinking the perk you will have no weapon.

Go over to a gun and buy it and wala... 3 weapons!