Amazon has the 3-Pack Culligan ZeroWater Official 5-Stage 0 TDS Replacement Filters for $33.74 - 10% off coupon (check “Save an extra” box, eligible on first S&S order for this product) - 5% off with Subscribe & Save (can cancel anytime) = $29 with free shipping on $35+ or with Prime (extra 15% off for 5+ subscribe and save orders). Certified to reduce lead, chromium, and PFOA/PFOS.