You are being hired because you know something that your client doesn’t. Your client needs your services and is hiring you specifically because you know what you are doing. That time, that effort, that expertise that has attracted you to them has a value of some sort. Now, I wouldn’t expect you to charge $50,000 just for your time to overhaul a WordPress website. Hell, if you did, I certainly wouldn’t hire you. So whilst you may feel you are worth $50,000, you will also have to factor in the going rate.