I'm not sure what you paid at Costco, or what BJ's is, but for years I have been buying my glasses online at warbyparker.com. Free home try-ons, never had a problem with their optics, and on the one occasion i had a frame problem they replaced it no-charge and gave me a partial refund. I own 7 pairs of their glasses.
You can get even cheaper at places like zenni optical. A friend of mine likes their glasses, but I'd prefer to try them on first before I buy.