American Home Maintenance Huge ripoff attempt - tech tried to charge me almost 10 times the cost of the part. Tempe Arizona

I walked into the local Home depot to be greeted by a guy offering me a ac/heating system checkup for a good price. I already had a problem with one of my heat pumps so I agreed to have them send someone. They finally had someone come a week later. I tried to tell the tech some background info about what was going on with that unit since I felt it might help him with the diagnosis, but he didn't seem too interested. Then he tells me that the Transformer was bad. Ok, so i asked him how much the part would cost and then he goes to his truck and makes some calls and quotes me $280. Now I'm an electronics tech and an electrical engineer and I'm not stupid about electrical parts. I paid him for the checkup and declined to buy the part from him. I found the same part, in fact a much better one (higher rating than the one he wanted to sell me) for exactly $30.
Excuse me, I'm ok with a mark up. maybe double or maybe even tripple the price, but asking 10 times the price, I call that highway robbery. I will never ever do business again with this company. I imagine that there are thousands of people that they are able to swindle because the valley is full of dumb people who are not technical and who wouldn't know how to check the prices. I will do everything in my power to make sure that more people know about these crooks who are primarily interested in parting people from their hard earned money.

Aintdumb
Peoria, Arizona
U.S.A.