A printer cartridge is the device that supplies a computer printer or fax machine with its ink or toner supply. Cartridges are divided into two separate types. Inkjet Cartridges contain liquid ink and are used in computer printers and fax machines. They are small cube-like devices that have to be changed when they run out of liquid ink. The other type of cartridge is the Laser Toner Cartridge. It is much larger and heavier than an inkjet cartridge, and it contains black and/or colored powder, known as toner. Laser cartridges are used primarily in business environments for higher volume printing. Inkjet cartridges are more often found in home or small business environments. Both inkjet and laser cartridges have to be replaced when they run out of ink or toner. Original Equipment Manufacturer (O.E.M.) replacement inkjet cartridges cost from $20.00 to $50.00, while lasers cost from $50.00 to $200.00 on average.