It seems to be that none of the above posters have any real overall strategy. You can save money using third party toners with the down side risk of a higher fraction defective.
So what happens when you have a defective third party cartridge? Are you going to shut down your whole office waiting for that free replacement or will you have at least one known good replacement? And a local refiller you are in driving distance of. By the time its mail order its at least three days at a minimum.
But point be you can save maybe 50% or so on Third party toner cartridges.
But if you really really want to save huge bucks on high volume laser printing, you change the laser printer you use instead. There are a lot of out of production HP industrial use high volume printers on the used market now. They use standard 10,000
page yield toner cartridges that also come in non-OEM. Using them and you can get to the close to 1/4 A CENT consumable costs. In production the printers used to cost way over a grand, but on the used market its only a Hundred or so.