If you don't mind some hassle to save $1, choose "Subscribe & Save".
Wait a week for your order to ship, then go to your Subscribe & Save Page, press "Your Subscriptions", and cancel the Oral-B replacement brush heads.
However, if you forget to cancel your Subscribe & Save subscription, Amazon will automatically re-order this product for you when the time you specified elapses, until you cancel.
Click the $15 coupon under the price, then click "add to cart."
During checkout, apply coupon code 20ORALBNOV1 to get another $20 off.
Final price is $55 with free shipping.
Be sure both discounts appear before submitting your order!
If you do forget to apply a coupon, Amazon makes it easy to cancel an order within the first 10 minutes, then you can place another order with the coupon.