Printer toner

Gramme for gramme, printer toner is more expensive than gold. No, really!

And another thing: the cheeky monkeys that make printer cartridges have made sure that the printer says the cartridge is empty WAY before it actually is. Then, when you return your old cartridge & get a new one, they pour the leftover toner from your old cartridge into a new one. They're selling the stuff over & over again!