A guy I work with (who has been smoking for over 40 years) has decided to try e-cigs after seeing how well they have worked for me (over three weeks now). He chose a starter kit from a cigarette shop. I advised that he get an extra battery but the ones sold by Pure Smoke are almost as much as he spent on the starter kit! Does anyone know what type of battery Pure Smoke sells? I know that they aren't 808's (I have a Volt 808 and the Pure Smoke batteries are thinner and have different threads). I'm thinking maybe a 510 (just a guess)? I'd like to try to find a cheaper alternative until he is ready to get a better kit down the road, but I want to make sure he has enough batteries to get through the day without having to buy a pack of cigarettes. Thanks in advance!