It's always nice to be referred by someone. The person who referred you spoke highly of you and your services. You could possibly have a new client, but that potential client would like to see your portfolio and the services/products you offer before making a decision. They want to know what you and your business are all about for themselves. The best way for them to do that is through a website.
Having a website is like a 24-hour call service. It's always available for information and it will help potential clients find the verification they are looking for. A website also gives the consumer time to make their next purchase without any pressure. And most importantly, it gives the consumer a way to contact you! Your business can be open while you're asleep.