Amazing Deals Online via Amazon offers Prime members the GoScope Optical Acrylic Red Filter for GoPro Hero 3 for $12.99 with free shipping. That's the lowest total price we could find by $12. (Non-members can spend $35 or more to bag free shipping; otherwise, it adds $5.74.) It features a secure snap-on connection, polycarbonate frame for durability, and microfiber bag for lens protection