I called Big O and asked for a quote for a tire and was $50-something. When I arrived the taxes and fees added up to $83, slightly more than the other stores had quoted me up front. I had the tire done anyway since I thought I should have asked about a total fee. I asked if I could buy oil because I have a leak and they said they'd check the leak and fill the oil no charge which was super nice.
Two days later my car wouldn't start and I called Big O to ask if they could help me and if the diagnostic fees were applied to the repair, he said yes to both. Car was towed there and they reported to me that I needed a repair that would cost around $400 and the diagnostic fee was $110. I explained that I called earlier and ensured that the diagnostic fee was applied to the repair. They said they don't do that and later offered for half of it to be applied. I was significantly angry at this point because I had been responsible and checked and they went back on their word. Eventually the manager called me back and said they would wave the diagnostic fee. I'm leaving out details for the sake of brevity, but it was a horrible experience and I did not feel heard or valued in the least.
When I was considering taking my car elsewhere for the repair (before they called me back) I spoke with a place called Sun Devils Motors which is family-owned and the person I spoke with was kind, supportive, and I had a sense of trust with him immediately, totally different that my experience at Big O. He said that at this point I would be better off financially to just get it done at Big O, but that they do not even charge diagnostic fees so I could use them in the future if necessary and that is certainly what I will do.