Absolutely, without question, selling music online.
There are still a number of ways to make money with music. Wherever there are people, there is music. The old ways of live gigging, cruise ship gigs, wedding singers, karaoke singers, session musicians and music teachers are still very popular.
It depends if you lean more to composing or performing. Or nowadays, tech. If you are a tech, look at recording studios or online media. If you are a composer look at writing and selling songs, hiring people to perform your songs and sell them online, or the still popular tv and movie placement through places like taxi.com.
Find out more about how to make money with music.