What is HP Instant Ink? You pay a fixed amount monthly, which allows you to print a set amount. If you're almost out of ink, the printer will inform HP via the Internet that the ink cartridges need to be replaced. HP will send you new ink right away, so you can print to your heart's content. Curious about how the HP Instant Ink plan works and which subscriptions HP offers? Read our advice page 'What is HP Instant Ink?' for more information.