If you are a first-time customer of Firmoo Glasses, you can get a free pair. They have 1,000 per day to giveaway on their Facebook page (around 500 left for today) so check back tomorrow if this is gone by the time you see this today.
What you get: free glasses including frames and 1.50 lenses. Lens upgrades and shipping are an extra cost (only $4.95 for shipping in most of USA!) and prescription sunglasses are an extra cost.
(Thanks, Dont Make Me Nuts!)