To purchase an AM/PM Permit, make check or money order payable to Montgomery County, Maryland for the full amount for one, two or three months parking and indicate the months being paid for. Mail to "AM/PM" Parking Permit, Parking Sales Store, PO Box 8399, Silver Spring, MD 20907. Parking permit will be mailed along with instructions and a renewal envelope. Please allow 2 weeks for request to be mailed back . Permits can also be purchased at the Bethesda Parking Sales Store, 4720 Cheltenham Drive, Bethesda, MD (within garage 42) hours are 7:30 am - 4:00 pm Monday - Friday. Cash, Check, Money Order, Visa or Master Card. they can also be purchased at the Parking Sales Store within garage 61 at 809 Ellsworth Avenue, Silver Spring, MD 20910. The hours are from 7:30 am - 4:00 pm Monday - Friday. Check, cash, Money Order, Visa or Master card accepted.