As of October 2015, coupons for the Sonicare toothbrush can be found on the website for Philips, the toothbrush's manufacturer. The website's coupon page has printable coupons for $15 off the DiamondClean, the FlexCare Platinum and Flexcare+.
The website also has $10 off coupons for the 2 Series and 3 Series toothbrushes as well as the HealthyWhite+ and the AirFloss Pro. The Philips site's electronic toothbrush page has descriptions of the available toothbrushes and links to the printable coupons. Through 2015, Bed Bath and Beyond is offering rebates up to $30 on Sonicare toothbrushes. The form for these rebates can be found on Sonicarecoupons.org.