Meritline offers the Canon CLI-221–Compatible Inkjet Cartridge 8-Pack for $17.95. (It's the second option from the top.) Coupon code "MLCA18HN" drops it to $6.95. With free shipping, that's the lowest total price we could find for comparable ink in this quantity by $4. (For further comparison, we saw a similar 5-pack for a buck less three days ago). These cartridges fit several Canon PIXMA inkjet printer models.