It depends on how much time in the test chamber you need and how many retests. It can be many $10k-$100K.
But since you can't really test until you have a production PCB layout and then you might have to move tracks or add caps/inductors/ground planes - the costs of a redesign are normally much much higher than the testing
This is why you sometimes see, for example, a device that is designed to accommodate RF shielding but the shield is not installed. It's cheaper to design the shield and then omit it in production if the tests happen to pass without it, than it is to risk failing a test and have to go back and redesign with better shielding.