walgreens.com has this 6-Ct Oral-B CrossAction Electric Toothbrush Replacement Brush Heads for $55.23 with free shipping. Instructions below.

• Clip the $5 coupon
• Add quantity of 2 to cart (for 6 total heads).
• Apply promo code CARE15 for 15% off
• Get $40.69 Walgreens Cash Rewards when you select free store pickup