According to JR Inkjet, the original Epson cartridges for this modelk cannot be refilled - their refillable ones ar £5.99 each - that make £23.96 a set.
http://www.xscomputersupplies.com/acatalog/Epson_Stylus_C64_C64_Photo_Edition.html
Our sponsor is £3.30-£3.60 each, or £13.05 a set.
Given the price drops of chipped clone cartridges, I'm not sure that refilling adds up, risk of mess, risk of fouling up the refill and contaminating the print head.
For "head in the cartridge" systems, refilling certainly does add up, as for those, the only alternatives are expensive originals, or refills that you do not really know the quality of - often poor, if run to bone dry before refill. And I've seen a HP Deskjet original, black wadding (original type) cartridge, run in pseudo-continuous feed, just shooting it with ink, using a home-made filler funnel through the vent hole (with the cartridge STILL INSTALLED) - it was everlasting!
PS. It's also rumoured the Epsons are more economical if you leave the power to them on, as they power off to a "standby" and will not perform a full startup cycle (including spitting ink into the waste) unless required by timer.
If powered completely off ** USE PRINTER OFF FIRST, to ensure it's parked the head if it needs to **, then it will spit every time.
Certainly, once you've used it for the day, and might use it again, you want to keep it powered, but put it to OFF so you don't forget - actually, they do park up fairly quickly, so if the printer has been idle for more than half a minute, the head is probably parked and capped already.