Boyfriend and I just picked up some 18650s from Frye's which is a computer mega-store. Works in his mech-
mod but throws an error code in the provari. If you have a friend-- I would just send them in to the battery
shop and have him buy three or four at a time. I'm actually on a hunt for a different battery that seems to only be sold from one source so I feel your pain but luckily, 18650s are pretty common.