Tire Kingdom

I was told that I needed an alternator for my 2001 Lexus, and when I saw the part alone was 400, I asked was it new. I was told its a rebuilt alternator. I reached out to a mechanic I trust and he agreed that that was extremely overpriced and to ask the specific model. I then reached out to tire kingdom and was told "we got it from Napa auto parts down the street." I then asked Jayson, the manger, why if Napa sells the same part for a little over 200, are you charging me DOUBLE for the part, when I could have had my friend pick up the part and drop it off! I get you need a little mark up, but 100%? When I mentioned this to Jayson his reply was "That's what the computer printed out". I was floored. This is an abuse of power and a poor reflection on customer experience. Please advise prior to me filing a complaint with the Florida authorities. Thank you