Printer A: $450, $0.12 per page at 15% coverage, 100 pages per month for 60 months.
Printer B: $390, $0.10 per page at 20% coverage, 100 pages per month for 60 months.
Okay, for printer A let’s say that the cartridge is rated at 500 pages at 15% coverage (i.e., which percentage of each sheet, on average, is covered by that color. Let’s say black to keep it simple, even though that’s a lot of coverage). This cartridge costs $60 ($60 ÷ 500 = 12¢ per page).
For printer B, let’s say 700 pages at 20% coverage, and the cartridge costs $70 (10¢ per page).
Now we’ve got to equalize the differences in coverages, because each manufacturer has rated them differently. So for printer B, 700 pages at 20% coverage is the same as 933 pages at 15% coverage, which for the $70 cartridge means our cost per page is really only 7.5¢ at 15% coverage.
So over a five year ownership period, total cost of ownership (barring maintenance costs, if any, and paper):
Printer A: $450 + (60 * 100 * 0.12) = $1170
Printer B: $390 + (60 * 100 * 0.075) = $840
Printer B is by far the better choice. Let’s swap the prices only, though:
Printer A: $390, total $1110.
Printer B: $450, total $900.
In this case, even though print B costs more money, and even though its cartridges are more expensive, is still the cheapest to own.