Double coupon! Amazon has the DenTek Professional-Fit Dental Mouth Guard for Nighttime Teeth Grinding on sale for $17.99 - 25% off coupon (choose "One-time purchase" then check "Apply Coupon") - 30% off (check “Save an extra” box, eligible on first S&S order for this product) - 5% off with Subscribe & Save (can cancel at any time) = $8.10 with free shipping on $35+ or with Prime.