Air conditioner blows hot air sometimes

1st let me say I'm very impressed with you guys, your doing a great services.
A/C gurgles (and clicks) and sometimes blows straight hot air (feels like straight from motor) until I turn off vehicle and restart. Happens summer and winter (when heat is on), I'm feeling confident that I need a "blend door actuator" but do I need driver or passenger actuator. Confusing part is I've been told the part is about $235, on ebay I see the part (same as what is replaced in the video) for $40 to $70. What am I missing.
Thanks for the help.

2005 Silverado Crewcab (Z71) dual air control.