Why isn't it free?
For $10, you receive the complete OSINT-6 Core Rules in both a printable PDF and an accessible RTF edition. The game is released under a free license, allowing you to use, share, adapt, and build upon it within the terms of that license. We believe that's a fair price for a complete roleplaying game while helping keep the project sustainable for everyone.
If it's meant to be open source and Creative Commons licensed, though, why isn't it free? There are two reasons.
First, every download from out site consumes storage, bandwidth, and web hosting resources. A nominal fee helps cover those ongoing costs so the site can continue providing articles, updates, and downloads.
Second, a purchase creates enough friction to discourage automated bots from scraping and mass-downloading the work. That helps to preserve bandwidth for readers, keeps hosting costs manageable, and protects the project's resources.
Finally, the individual System Reference Documents are available for free on the respective section pages. They lack the introduction, the table of contents, the index, and the appendices, but the complete core rules, character creation, equipment, and operations rules are there in rich text (RTF) format for you to use.