Electrical shortage

My radio has began popping at start-up and after a couple of minutes of going in and out it works. As it goes in and out the radio turns up as I turn it down. Also, the lock button on the keyless entry doesn't lock the door, when I hit it the back door makes a locking sound twice but does not lock. Now the drivers side door will not lock or unlock even when manually hit on the door. What may be wrong and how much should it cost to fix? Thx.