Digital BW, The Print

I received my epson 2400 over the weekend and yes it is a very nice 
printer!  However now I realize what people have been speaking about 
regarding ink usage, WOW!  After a couple of small test prints, a 
change from the matte to pk black I have a bit less than 3/4 of the 
ink left.  Any suggestions outside of yelling at espson for clearly 
boosting their ink business?  Also are the MIS inks for the 2400 
significantly different in price to warrent their use?  Any 
suggestions or thoughts would be helpful.  Thanks

JOe