I bought my aids from an audiologist employed by Costco. I also saw her on her last day. She was moving to a hospital center (talk about outrageous markups) for more money, fewer hours, and perhaps a more interesting clientele.
Costco is great in many ways, but it isn’t perfect.
The only private audiologist I’ve consulted with did my hearing test and told me I needed a pair of aids for $6,000, with no explanation of why I needed that specific pair or what my options were. It took me 3 years to get up the courage to go to Costco, and I did that mainly because of the recommendations I got.