What is considered good HVAC pricing? Central TX area

[Stone Saathoff]

Curious as to what other investors have had to pay for a full HVAC install, new duct work as well. I deal with houses in San Antonio on a regular basis that don't have central HVAC and I've heard a pretty broad range of pricing even for the same property to do a new install.

What size houses have you done a full central HVAC install on and how much did it cost?