Was looking for a refill option for canon 645/646 Cartridges and found these ones. seems to be an amazing price!
These Calidad 921-CPOW Canon Compatible Ink Refillers will give new life to your old ink cartridges. The ink will deliver crisp and clear printouts on a wide variety of paper. Using these refillers will not void the manufacturers warranty.
Compatibility : PG-37, CL-38 PG-40, CL-41, PG-50, CL-51, PG-510, CL-511, PG-512, CL-513, PG-640, CL-641, PG-645, CL-646