online glass stores like ZenniOptical usually use slightly lower quality frames to get such low prices. Though many frames are the exact same you will find for hundreds of dollars at a brick and mortar glass store, I haven't found items like flex titanium that are the same quality of even those I purchased at Costco for $60 (frames only!). Thats not to say glasses are grossly marked up in tradition retail locations.

But, I personally have 2 frames from a similar online eyeglass retailer, one I use for driving sunglasses and the other as a backup, both look very good on me and are constructed of titanium. They don't flex as well as my costco titanium frames nor do they feel as sturdy, but for the cost I couldnt care less. The total cost of frames and lenses were under $50 shipped