In most cases - nothing! In fact, you should be able to make more than enough in the growth of your company to pay for the coaching. And, the results last for years after the coaching process has ended. It's the greatest investment that you will ever make!
But if that's not a good enough answer, we'll tell you this: It would cost you more to hire a receptionist to answer your phones for a year than it will cost you to hire a coach. Think about that.