With the (BOP)discount phone line 300 mins. per month. If you use up the 300 minutes before the month is over will I have to wait until after 30 days to make another purchase

The 300 minutes that the inmate gets to use on a per month basis resets the same day every month by the BOP, however, that date is different for each inmate. The Service from InmateAid recharges every 30 days for only $5.