Most printers have a Cost Per Page (CPP) figure in the top right.
Cost per page is calculated using the cheapest available OEM (original) cartridge or bundle provided:
a. It is supplied by the manufacturer (or by Computer Food as a replacement for a specific OEM bundle) and
b. The cartridges in the bundle (if available) are used by the majority of customers.
c. The bundle is a long term offer from the manufacturer and offers good savings.
d. Combined Colour / Black bundles are excluded as they would require a cost allocation between black and colour.
For example we eliminate the Canon CLI526 5 pack as the CLI526BK is only used for Photos and so not useful for many customers.
Colour CPP assumes users print black and colour approx in line with standard ISO rules.
Photo printers are generally excluded as no proper CPP details are available.