The iP4500 uses one of the newer generation of Canon ink
cartridges, the #05/08. The iP4500 ink is cheapest in the compatible cartridges. This ink for the iP4500 has a similar page yield and quality to the original but is much less than newer Canon models such as the Canon MX870 ink
that is much long lasting, cheaper and of a higher quality.
These cartridges are still fairly common however as the iP4500 ink jet printer is known to be very durable and long lasting. There are compatible, remanufactured and OEM cartridges available from inkfarm.com