Hi, welcome to Just Answer. I'm acuramstr. the parking brake is a set of shoes inside the rear brake disc they can get rusty with time and stick .But if you havent used the parking brake lately it could be the regular rear pads that are worn-out .They have a device that makes noise when the lining is worn. As far as cost goes in my shop rear brakes run about $189.00 and the parking brake lining about $225.00 .however I cant see your brakes and you may need other parts, cables ect. so these estimates are only educated guesses. If there is anything else I can help you with let me know .