Let's assume for the moment that anything that a user needs to search for already exists in the database in some recognizable form. For example, if you want Drupal to understand that a product has a certain tempo, you are either going to manually tell it or use getid3() to get at that metadata https://drupal.org/project/getid3. So, we have data. Now, to be able to create a searchable catalog similar to what you would find on NewEgg.com (faceted search results), you will need an awesome combination of:

Views
Search API
Commerce Search API to tie it all together: https://drupal.org/project/commerce_search_api

This is the method used to do the Commerce Kickstart 2 catalog. It allows to have searchable faceted search results. You can play with it here:

http://demo.commerceguys.com/ck/products?search_api_views_fulltext=Drupa...

First "search term" is a bit of text I typed in. And the second is a facet based on the kind of product I wanted (shoes). So you can imagine how this would work with your catalog for music.

Now, to handle downloads of products, I really recommend https://drupal.org/project/commerce_file which extends Commerce License with downloading capabilities. That means you can manage access to the music based on number of downloads, etc.

To share "previews" you could use one of the many Drupal 7 Audio options:

https://drupal.org/project/audio_js
https://drupal.org/project/audiofield
https://drupal.org/project/opigno_audio_app
https://drupal.org/project/mp3player

... though, for the most part you should probably just use the Drupal 7 core filefield and use one of the modules above for the formatter to turn the mp3 into a player.

To connect artists to their music could easily be done through an entityreference field.

https://drupal.org/project/entityreference

Basically, it gives you a two-way reference that you add as a field to the product displays and you could then list the music on the artist's page and the artist's info on the music page using Views.

Yes, there's lots to learn. Definitely want to learn Views, Rules, Nodes, Fields, and the theming system.

Josh