With the Free plan, users can listen to music on-demand, but with some limitations. For example, users can only skip a limited number of songs per hour and cannot choose to play specific songs or albums. Additionally, Free users are subjected to audio advertisements between songs.
To access the full Spotify experience, including all of the songs in its library, users must subscribe to the Premium plan. Premium users have unlimited skips, can play any song or album on-demand, and can listen to music offline without an internet connection.
Therefore, not all Spotify songs can be accessed via Free. Some songs may only be available to Premium subscribers.