BHrake pads are cheap to replace (~$100 incl. labor). When brake pads are gone, everytime you step on brake, it's doing some harm to your brake rotor. If your brake rotor is damaged, you will need to pay $300 to get it repaired.
Go to your dealer immediately. It's dangerous to drive with that condition.
Because a car get 4 breaks.
Check it out before you have to replace the rotor. $300 may be just for parts. plus labor and tax, you are looking into $600. : (