There is a new printable available for $3 off a 3 Pack of Britta Replacement Filters! Take this over to Walgreens through April 20th and you can use it for this scenario:
Brita Replacement Filters 3pk $14.99 (through 4/20)
-$3 Britta Coupon (direct link)
-1,500 Balance Rewards Points (worth $1.50)
Amazon is currently selling the Britta Filter 3pk for $16.92 so this seems like a very nice deal.