yeah i dont really know either, i guess you just have to buy a bunch of them...
and how long the last would deppend on how you drive. I've never done it that way so i couldnt tell you...
but yeah somebody5788 let us know cuz im plannin on gettin some soon....

 

Well I am def getting some for christmas haha. If I get the wholesale price ill let ya know and will only keep a 20 for myself haha so you should still get a great deal.