Amazon offers the Philips Sonicare ProResults Toothbrush Head 3-Pack for $17.60 with free shipping, via the below directions. (Target has it for pennies more when you add it to cart as a subscription.) That's at least $12 less than you'd pay at a local retail store. They are compatible with DiamondClean, Flexcare, HealthyWhite, 3 Series Gum Health, 2 Series Plaque Control, and Essence+ handles. To get this deal:
  1. View the Philips Sonicare ProResults Toothbrush Head 3-Pack for $26.95
  2. clip the $8 coupon on the product page
  3. add to cart via Subscribe & Save for a final price of $17.60
Note: Be sure to cancel your subscription after your order arrives to avoid being billed for subsequent purchases.