As one of its daily deals, That Daily Deal offers two pairs of Columbia Sports Polarized Sunglasses for $14.99 with free shipping. That's $7.50 per pair and the lowest per-pair price we've seen for this brand. (It's also a current price low for two pairs in any style by $17.) They feature polycarbonate lenses. Deal ends April 22.
Note: These ship in random colors and styles.