ValleyBuy via Amazon offers Amazon Prime members the Canon PGI-220 / CLI-221 Compatible Inkjet Cartridge 12-Pack for $9.67 with free shipping. (Non-members can spend $25 or more to qualify for free shipping; otherwise, shipping adds $5.72.) That's tied with the lowest total price we could find for a smaller 10-pack. It includes four PGI-220 black, two CLI-221 black, two CLI-221 cyan, two CLI-221 magenta, and two CLI-221 yellow compatible cartridges.

Amazon Prime membership is $79 per year; however, Prime is free for college students for six months, and free for parents and caregivers for three months. (Note that currently there's a waitlist for Amazon Mom.)