This is a pretty hot topic on the internet right now, some people are satisfied and some people aren't.
I found a 500$ dollar gift card in Backpacker for a company called Red Star World Wear. These cards have been found by tons of people in all kinds or different magazines.
Pretty much, you have 500$ dollars to spend on any items in their store. BUT, you have to pay a 9% "Service Fee" on all the items that you buy. For example, if you buy a 130$ pair, you end up paying roughly 12$. The service fee is a minimum of 9.90$, so you pay 9.90$ for any item that is priced at less than 110$
Nobody knows where the fuck they get they're supposed retail prices.
So, in the end, its not free. But its not a total scam either. People did get their glasses, and they look pretty cool. They're just as durable as any 10$ pair of glasses, but I don't really care about that because these wouldn't go through any abuse, they would just be street ware.