I found the company though a deal on Teambuy. They offered a deal on duct cleaning and anti-microbial disinfection for one main trunk and 10 hot heat vents for 79$ and 12.50$ for each additional cold air return vent, 25$ for each additional trunk and 7$ for additional vents. These prices seemed reasonable to me.
My call was returned a few days after I left a message. The receptionist was very nice and booked me in the following week. The technician arrived on time, went around the house and counted the ducts, trunks, and cold air return. He then asked if I wanted to have the additional vents done and gave me a quote before starting. I thought they were very courteous and professional. I would recommend this company.