It uses KR808D-1 threaded cartos. You can use and standard resistance KR808D-1 blanks like the ones at LiteCigUSA.net
What saves bucks is keeping your cartos damp with
eliquid to get several days use out of each. Be extra careful though since you have auto batteries. Make absolutely sure a refilled carto is not going to leak before you put it back on your battery because the place a carto might leak is right where
juice could damage or kill an auto battery. KR8 manuals still have a hole in the end of the battery but at least are not dependent on a drag sensor sitting right inside the hole - it would take more
juice to damage a manual.
Vapesafe has cheaper KR8 cartos but they are harder to refill and/or not as good when refilled. They may have hard or glued on caps. I have not tried them myself. Someone else told me that. You could also check Smoketip's carto price and I knwo nothing about the caps of their cartos. I only use soft-cap cartos from Vapor4Life and manual batteries and I top off the cartos with juice as I use them.