When my $50 laserjet runs out of ink (going on 3 years now; I don't print much), I may just leave it at the end of the driveway and get another $50 printer, even if the > $50 cartridge would last longer than the starter cartridge.
You should check check the prices first. I know I looked into Brother lasers, and the preinstalled cartridge is only rated for 600 pages. A high-yield black toner cartridge is only $47 and prints 2600 pages. And $50 doesn't get you much of a laser printer.
And the rating of 600 pages is low, it is determined in software on the starter toner. On my brother, there is a small hole on the cartridge that light is passed through to detect the toner level.
My printer is at 3200 pages on the starter toner because I put a piece of tape over the sensor which makes it believe it is always full of toner.
New printers from Brother which I bought the same model for my in-laws, have solved this hack. But you can buy a replacement gear online for a few bucks, it pops on, and then you have access to the same method I used to trick the printer.
Once the stater runs out, I will get a toner replacement and also tape the sensor. Even if it prints a little light, all it takes it taking the cartridge out and shaking it a little. This will buy you another month.
If you are on Mac OS X or Linux and access the printer through CUPS, ( not sure about Windows and how to access these settings ) and you can set the DPI to a lower rate and put it in toner saver mode. I can't tell a difference unless I have a side by side to compare. Plus, this is just black and white so invoices, driving directions, stuff like that. I don't care about the quality of a halftone image.
Should note that doing this can damage the printer. The toner particles that don't stick keep getting recycled back into the cartridge until eventually clumps of that crud are most of what's in it, and you're still trying to use more and more voltage to pull it out onto the paper... possibly getting it stuck somewhere else in the printer, damaging the drum, clogging a fan, or any number of risks.
If you're 5 times past the rated capacity of the cartridge and it's printing light, instead of shaking the crud around and putting it back in, just buy another cartridge... unless you WANT to destroy your in-laws' printer and burn their house down.
You can buy a decent Brother monochrome laser printer (auto duplex, wireless, and wired networking) for ~$60-80 on sale and the generic toner for $10-20 for 2,600 pages.
For most people this is a far better option than buying the Brother brand toner. Worst case, it ruins the printer and you buy another one for that $50! I have had great success with the generic toner so far, nothing ruined or leaky yet.
