I've been doing some math - and after the initial investment on the equipment (which will pay for itself with the $$ I save not buying analogs) and once I get through my pre-filled cartos (which will only benefit me because I can re-use them when I am filling my own) - and which I will alternate with my own refills..it sure looks to me like if it takes about .9 ml to refill a carto @ around $16.95/30 ml (ordering enough to get free shipping) is it really down to .57 per carto? I use 1 carto per day. That's $4.20 per week? Holy crappola!! For me personally, that is a savings of $200 per month.