Buying a new ink cartridge for your printer can be a hassle, but the internet has made it quite a bit easier. Ink cartridges are available for sale on Amazon, OfficeDepot.com, and Newegg, which regularly feature sales of printer ink and other products. Ink cartridges can also be bought directly from manufacturers such as Epson, HP, Canon, and Brother. There are many models of ink cartridge available, so always be sure to order the same type of cartridge as the one you intend to replace.