re: Costa Sunglasses from Amazon

Depends if the retailer is amazon proper or some other third party who sells through amazon. I trust amazon completely. Second is retailers who sell through amazon, but have established websites of their own like backcountry.com. Third are retailers who have orders fulfilled through amazon. Most untrustworthy, retailers who are none of the above. The last category is most questionable because they are essentially using amazon like ebay.