Well, after my initial trying stuff phase I settled into using a 510 with a drip tip with unflavored 36 mg and straight vg dripping when I just want vapor and no nicotine. I replace a battery every other month or so and an atomizer every month or so. A 15 ml bottle of unflavored lasts me almost a month. I picked up my VG from a store for about $6.00 and still haven't really made a big dent in it. So, let's see $15.00 for a battery, $10.00 for atomizers, and $30.00 for juice comes out to about $60.00 every other month, which translates to about $7.00 per week. I stick with DFWVapor; never had any issues, he's fast, and he's very helpful.