We live at an orphanage and want to bill each volunteer for their internet usage. We only have 3G, no DSL. We would want to use a dedicated laptop to plug the 3G dongle into then use a router to broadcast the signal. We would like software to track each users usage so we can bill the volunteer. We don't have money to spend on this and have the hardware. Please assist on how this can be done. We also thought we could do a prepaid solution.