At this moment we are not providing beta, alpha, release candidates, etc versions, but you can install it on your own on top of a LAMP instance.
Bitnami LAMP Stack provides a complete, fully-integrated and ready to run LAMP (Linux, Apache MySQL and PHP) environment. You can find more information and use it following this link https://bitnami.com/stack/lamp.
Once you have a LAMP instance running, you can download and install Drupal 8.5rc-1 from upstream.
Also, you can take a look at this guide, probably you will find it useful:
Carlos R. Hernández