Most Cashdrawers receive the signal to open from a receipt printer. If you use an EPSON receipt printer then you must have an EPSON interface for your cashdrawer.
TOUCH MONITORS
http://www.allthingspos.com/elo/
PRICE TAG PRINTERS
http://www.barcodesales.com/zebra/2824.htm
LP 2824 is the current low cost model-----Serial or USB interface since parallel port is probably in use with receipt printer.