I would say that these days "professional" starts at MSRP $600 and "high quality" at $1000. This rules out anything you'll find at the nationwide B&M office supply chains, Best Buy, etc.
Keep watching CL. You WILL find the $600 chairs for $100-$200 and the $1000 ones for $300-$600. If you live in a smaller city use the CL of a larger one nearby (that's what I had to do).
If you can't wait: Look around for local companies that specialize in supplying businesses with used office furniture. The good quality stuff lasts forever, so this is a thing. It will be more expensive, but still cheaper than new.