You can download the Unraid USB Flash Creator and start a full-featured 30-day trial with no device limits.
Unraid does not have a permanent free tier, but it offers one of the most generous evaluation periods in the industry. unraid free
Unraid is a popular operating system that allows you to create a secure, reliable, and highly customizable storage server using your own hardware. And the best part? You can get started with Unraid for free! You can download the Unraid USB Flash Creator
Note: If you choose not to pay the optional $36 annual extension fee for Starter or Unleashed, you keep your current version forever but lose access to new OS updates. unraid free