Also available, Amazon has 6-Count Colgate Extra Clean Full Head Toothbrush (soft) for $3.93 after 'clipped' 30% off coupon (clipped automatically through link while logged in to Amazon) and checkout via Subscribe & Save. Shipping is free. 

Note, you must be logged into your account. Coupons are typically one use per account. You may cancel your Subscribe & Save subscription any time after your order ships.