7. Buy knockoffs
I'm not talking about buying a fake Rolex: I'm referring to buying supplies from "non-OEM" suppliers. For example, in today's world, HP will sell a printer at a loss because they are counting on you to buy their ink for the next few years. The printers now even come with starter cartridges only half full.
I can get on eBay and find a compatible cartridge for as little as a quarter of the price, including shipping. It comes from Asia, and may even be produced by the same company producing the OEM version. Now the printer documentation advises you that using non-OEM ink will render the warranty void, and cause your printer to self-destruct, but I haven't had issues, just savings.
Payoff: Two toners a month, saving $60 per cartridge = $1,440 annually.