By reading some of the reported problems, I think I may have an actuator A C bad

cost for one what?

Depends on which actuator, as there are four. There are two temperature actuators (driver and passenger side), a mode actuator, and a recirculation actuator. The driver side temperature actuator is under the dash on the driver side above the pedals and is easy to replace. The other three are much harder to reach and usually require removing most of the dash. The parts run from around 70-270 for OE, again depending on which one has failed.