BEAR Solutions
We have used these systems on the Toshiba's (All series other than eS207's and the like). The students use their student ID card (which has a magnetic strip on the back) and put their card into a recharge machine. Enter in money and the card is good to go.
The ammounts on the card are held at a central server, so if the student looses their card, the ammount can be recovered.
Everything runs over IP and can be remotely managed.