J Tuo via Amazon offers the Zacx 180° Full Face Snorkel Mask L/XL for $32.99. Coupon code "OFSVHN33" cuts that price to $19.99. With free shipping, that's $12 off, and the lowest price we could find. It's fog free, features a GoPro mount, and includes a carrying bag, waterproof phone case, and earplugs. Deal ends July 31.

Note you can also grab them in S/M for the same price with no coupon necessary.