I'm new to the game guys so please hear out. My cousin has a green smoke with many cartridges. I want one but it is too expensive. Looking to buy just a battery and charger that will fit his cartridges. I know it is an e9 model and have researched brands like red dragon, loong totem, smoke 51, e-cig.com. I'm a broke college student trying to kick the habit. any suggestions on the best battery that will fit a GS cig? Thanks guys