I am getting mightily hacked off with an advert on Classic FM for the Canon something or other "photo printerrrrrr!!!!" which is currently sporting a free battery pack (£50 apparently)but would remind all that this is rather like razors. They give you the razor for sod all, but you will get badly and yet closely shaved when it comes to refills.
In a month or so, this will be no great problem as the compatible cartridge manufacturers will have their head around new models by then, but in the meantime, be warned!
Conan