the price of a blank cart (5) is (essentially) the same as a filled one, $10.00.
why would you ever use a blank one?
lets say my favorite flavor is caramel, and i buy some caramel juice
why would i want to load up some blanks with it?
it seems to make much more sense to buy a 5 pack of caramel carts, and when i finish a cart to then refill it.
this seems pretty obvious to me, which means there is probably something i dont understand