Glasses USA cuts 50% off most items sitewide via coupon code "JAN50". Even better, the code also yields free shipping. Although not as sweet as our November mention (which included $20 cash back in addition to 50% off and free shipping), it's still among the best discounts we've seen from Glasses USA. Eligible items include single-vision lenses and frames from brands like GUESS, Kenneth Cole, Lucky Brand, and more. Frames marked "Premium" are excluded. Deal ends January 31.