As of today, Apple's productivity suite is now available as a free download for all iPhone, iPad, and Mac owners. The core suite includes Pages, Numbers, and Keynote, but GarageBand and iMovie.
For those not familiar with the apps, Pages is a word processor, Numbers is spreadsheet software, Keynote is like PowerPoint, GarageBand is a basic music creation studio, and iMovie is basic video editing software.
Here are the links to the respective App Store pages -
Apple has actually been bundling these apps for free with new devices since 2013, but the change means that now even those with older or used iPhones, iPads, or Macs can download away.