hello, where is the best place to get 18500/18650/18350 batteries and a good charger for those, i want to buy the provari, but i might try the vv first with the tox cannon, i just dont want to buy the wrong batteries and chargers, i heard the charger with the tox isnt very good. and i want an extra battery, and are all 18500 etc the same does it matter. thanks