If you want to do it yourself, places like Squarespace and GoDaddy have templates and simple processes so you basically fill in the content and publish and you have something pretty quickly. This will likely limit you to their templates so less flexible. But that will get you a Version 1.0 and you can always determine later when to move to a Version 2.0. The beauty of digital is it can easily be changed.
Even with a simple site, I would recommend engaging a marketing professional to review your content. Otherwise you can end up with a site that looks pretty, but doesn’t put your firm in the best light or connect with your intended audience. I can pretty much look at a website and tell if it was self-created or professionally done. Since I’m a techie, I chose to put my time rather than my money into my site since once I knew what I wanted it to look like, I could easily use web building tools to make it happen.