Shnoop offers the Oral-B Sonic CrissCross Bristles Replacement Brush Head 8-Pack, model no. SR18, for $23.99. Coupon code "VITALITY2" cuts it to $21.99. With free shipping, that's the lowest total price we could find by $2. They're comaptible with Oral-B Sonic Complete and Vitality Sonic electric toothbrushes.