For Prime members only, Amazon offers the Philips Sonicare HX7022/30 E-Series Standard Replacement Brush Head 2-Pack for $11.72 with free shipping via the steps below. That's $6 off list and the lowest price we could find. It's compatible with Sonicare Advance, Elite, Essence, and Xtreme series handles. To get this deal:
  1. View the Philips Sonicare E-Series Standard Replacement Brush Head 2-Pack for $17.60
  2. clip the $5 off coupon on the product page
  3. order via Subscribe & Save for a final price of $11.72
Note: The HX7022/66 model is available for the same price via the above discounts. That's tied with our mention from three weeks ago and the lowest price we could find by about a buck. In addition to the above listed handles, this model is also compatible with the CleanCare.

Be sure to cancel Subscribe & Save after your order ships to avoid being billed for subsequent shipments.