Groupon offers the FreeBreather Full-Face Snorkel Mask for $43.99. Coupon code "SALE3" cuts it to $39.59. With free shipping, that's a buck under our mention from three days ago and tied as the best price we've seen. It's GoPro-compatible and comes in sizes S/M or L/XL. Deal ends May 21 at 8 am ET.