Jazzaria is home to two types of music:

Originals/Commons Covers
License CC BY-SA 4.0 Copyright/mechanical license
Sources Original, public domain, fair use, other Creative Commons works Anything post-Mickey Mouse
What you get for free Downloads, royalty-free reuse (including commercial) as long as you attribute Jazzaria and use a similar (libre) license Sample snippets, commercial streaming (Spotify, Deezer)
What you can pay for Royalty-free reuse without the share-alike clause, commercial services Commercial services (iTunes, Amazon MP3, Google Play, etc.)

Or more simply, Jazzaria is about freedom, and the music here is as free as feasible. For original work, you can listen to, download, and reuse/remix (even commercially) the music you find here. For example, you can use music here as a soundtrack for your own projects, or sample it for your own music, and release your work either freely or commercially. The only requirements are to attribute Jazzaria as your source and use a similar license for your work. An example of proper attribution:

(Description of what material you used and potentially how it was altered) was originally created by, and is reused here under a CC BY-SA 4.0 license.

To choose a compatible license (satisfying the SA clause), see the Creative Commons essay on understanding Free Cultural Works. The easiest thing to do is just pick the same license used here (CC BY-SA), but you can also use the straight attribution license (CC BY) or dedicate your work to the public domain (CC0).

For work that is a “cover”, it is not possible to give it freely and so instead it is made available for purchase through standard channels. Original work will also be available through these channels, and additionally can be purchased at lossless quality (FLAC) and with the option of reuse without the SA clause (licensed CC BY). Other outlets may also sell more commercial (competely non-CC) licenses for reuse.

Aside from the above usage rights, Jazzaria maintains full copyright on all material. If you wish to obtain more detailed aspects of the work (e.g. tracks/“stems”, notation, MIDI data, etc.), reuse commercially without attribution, or commission custom work, then you can contact Jazzaria through the “Feedback” link available on the side of the front page.