Making An Agency Site

I've started to have more success in my SEO career and for the most part I really enjoy it; however, I still don't have an agency site. I live in a big city, so ranking this site would be a lot of hassle, and I don't think many people organically look for SEO companies. But I do know that having a website is a great way for people to interact with your business, and it's essentially having a business card online. Should I create an official agency site? and If I do is it worth the money and time to rank it?