I just bit the bullet and paid $82 for the toner cartridge for my Canon MF5770. I've only tried aftermarket ink cartridges once...and it was a BAD experience. (leaked all over and ruined the printer) As much as I'd LIKE to save $30 or more on the toner cartridge, that one bad experience left me with a terrible opinion of the refillers/remanufacturers of printer cartridges.
OP, while this may get you by for the immediate, you're gonna need a new toner cartridge sooner or later for both printers...unless you buy a dozen of them now and keep the cartridges...
Unless there's been a big change in functionality between the time you bought yours and the newer one, why play the "disposable printer" game?