Toner/Inkjet cartridges is a big racket and they are very aggressive on protecting their gravy train. It is really bad in the inkjet market where many cartridges are still 10-30% full and for 99% of people get trashed.

I used to run a continuous ink system for my photo printer to just feed it raw tubs of ink. Canon, HP, and others have all been sued for their printer lines. Many times it is cheaper to just buy a new printer with starter ink as they are generally on aggressive sales than to buy new ink.

I just refilled the toner on my home color laser, from Canon it's almost $400, but I got an entire off brand set for $55 off Amazon.

That being said,the off-brand maarket is just as aggressive as the name brand at getting your business. When I used to work with companies, we used to get pressured hard to switch toner brands.