Amazon has the well-reviewed 4-Pack Brita Standard Water Filter Replacements (White) for $20 - $4 off coupon (check "Apply $4 coupon") - 5% off with Subscribe & Save (can cancel anytime) = $15 with free shipping on $35+ or with Prime (extra 10% off for 5+ subscribe and save orders). One filter lasts up to two months or 40 gallons.