Kinglooyuan via Amazon offers the Looyuan Hepa Filter for iRobot Roomba 700 Series 12-Pack for $16.99. Coupon code "86589U8H" drops it to $11.89. Plus, Prime members bag free shipping. That's the best price we could find by $2. It's compatible with iRobot Roomba 760, 770, or 780. Deal ends May 19.