Amazon has the 90-Count Efferdent Anti-Bacterial Dental Appliance Retainer Cleaning Tablets (Minty Fresh & Clean) for $4.12 - 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) = $2.67 with free shipping on $35+ or with Prime.