I can't help you out because the only time I called one out, he wouldn't take my money. We wanted to remove the old gas insert that came with the house and go back to wood. The guy pulled out the liner, inspected the chimney for safety, told me where I needed to fill the gas line hole with heat resistent mortar and recommended I call him back for a cleaning later, when it was nicer out. Funny story, a guy came out and capped the gas line for free too. It was strange.
My guess? $150?