TonerDeal via Amazon offers a Canon-Compatible PGI-225 / CLI-226 Inkjet Cartridge 10-Pack (pictured) for $2.70 plus $4.99 for shipping. Outside the price below, that's the lowest total price we could find by $4, although we saw this quantity for $1 less in November. These cartridges fit several types of Canon PIXMA printers.

A close price: Meritline has a similar 10-pack (two 5-packs) for $7.95 via coupon code "MLCQ29GN", with free shipping.