ArcoLinuxL, ArcoLinuxS, ArcoLinuxD and ArcoLinuxB is available for free.

You can download it and make as many copies and installations you want. All you have to do is download the iso and burn it on a usb and boot from your media.

our advice
install just one OS per ssd or harddisk
and avoid frustrations

our advice
use etcher as burning app

Dual booting, encryption and more is possible and will be set in Calamares, our graphical installer.
Many configurations are possible with Calamares and are discussed in this article.

What iso to choose