some can be quite expensive. i purchased a silver bullet mod from altsmoke.com with a battery and charger for around $135 and you will also need a tank and cartos. i use a phiniac glass tank because it fits well on the SB and its made out of pyrex so it wont crack when using cinnamon or other flavors that normally crack plastic tanks. its a little more pricey ($40) but worth it over buying severa