Those cartomizers will each last 3-4 days. Batteries need to be cleaned out at the screw end with a thumbtack and an alcohol pad once a week (make sure to poke through the air holes around the base), and with such maintenance will last at least 4 months with 4 batteries in rotation. Tanks probably last as long as anything else with a rubber washer.
So it's a little upfront cost. Now I have 3 flavors I know like and a tank for each, 2 chargers at home and work, etc., and I use long batteries because they keep charged longer (short is basically one AAA, long is 3). So my weekly cost is 2 $3 cartomizers, and maybe an entire $11 bottle of juice and ~1/5 of a battery's life -- $23. Versus smoking where I easily shelled out $60 a week.
No more tar neither.
And again, you can shop around / wait for sales / etc. I'm happy with this outfit simply because deliveries are prompt.