Apple has made the beta version of its web-based iWork suite free for users who don't own any actual Apple hardware.
Previously you needed both Apple hardware and an Apple ID to qualify for the seemingly-perpetually-in-beta iCloud version of the iWork suite, but over the weekend Apple removed the hardware owning restriction. So you’ll only need to sign up for an Apple ID to take advantage of Apple's productivity suite online, which for the moment is an entirely free offering.
There are plenty of competing office suites in this space — Google Docs and Office Online being the most obvious — and it's equally clear that this is an ecosystem play towards non-Apple users by Apple. If nothing else, it gives you an easy way to read an iWork-formatted document on a non-Apple machine with minimal fuss.
Beta iCloud [Apple]