The only savings you might consider would be to refill your cartridges with
bulk aftermarket inks from a decent vendor. In the US this ink is available
from Hobbicolors, MIS, and Alotofthings (Formulabs inks). Unfortunately,
the new chipped cartridges are designed to discourage refilling. When they
register empty and you refill them the printer recognizes them as empty and
gives you dire warnings. You can bypass these warnings but you will then
lose the ink monitoring system and will have to rely on visual checking of
the ink levels to avoid running a cartridge dry and ruining your printhead.
For more information look up the Nifty Stuff Forum.
http://www.nifty-stuff.com/forum/