You can't modify the printer but you can save money by using remanufactured cartridges.
Original Dell cartridges cost around �25 (black) and �43 (colour) for the high capacity versions. You can save between 33% and 45% (depending upon quantity) on black cartridges and between 58% and 65% on colour cartridges by purchasing remanufactured cartridges from InkCycle (which receives my highest praise,m both for the quality of their products and for their excellent customer service):
http://www.inkcycle.co.uk/default.php?cPath=13 63_1978
Chris