Just after some ideas on how to implement a sort of bar-code reader for a canteen, where i work we have about 750 employee's and my supervisor has asked me to get some stuff together for this sort of thing

Basically what we want is everyone will get a card with a bar-code or something (just to specify its them) and the canteen lady's will get a scanner or two. Lets say bob smith wants a sandwhich, we want to use this so they can put it on a tab and at the end of the month we bill them any ideas of software and hardware??