@Jagley It's impossible to compare ink usage/pricing across machines - it's totally dependent on number of pages printed - documents or pictures - quality and size of the pictures - usage and size of ink cartridge/container - someone else can construct the Excel formulas to work lot that out.
I print one or two pages every two weeks for me - about thirty pages every six months or so for an organisation I'm involved with - and about 200 pages every two years for another organisation I'm involved with.
It you're printing quite a lot I suspect the Epsom system might be easier - although you'll (probably) be paying full price for the Epsom ink.
I get a low/yellow warning when the ink cartridge gets low (clever eh?) and a red/empty warning when the ink cartridge gets, er, empty.
I order a new cartridge as soon as I get the low warning - see postage times below.
I get my compatible toner ink cartridges from www.internet-ink.com - I find their ordering process and prices the best - after 3 orders (I think) you get an extra 10% off your order and sometimes at Christmas you're offered 15% off.
The only slight problem is that I must not update my Printer's Firmware - this is what Canon do to force you to use only Canon cartridges although there are ways round this.
Hope this all makes sense!