Proozy offers the Superfeet Unisex Charcoal Insoles for $31.99. Add two pairs to cart and apply coupon code "DNSALE" to drop the price to $31.99. With free shipping, that's $16 per pair, which is $3 under last week's mention and the best per-unit price we've ever seen. (It's a low by $18.) Buy Now Features Available in men's sizes 4.5 to 11.5 and women's sizes 6 to 12.5.