As well as Audiojungle, I sell game soundtracks and short film / independent film soundtracks on Bandcamp.
A couple of these are available on iTunes, AmazonMP3, etc… but Bandcamp is a much better deal as there is a higher commission for the seller (only 15% goes to Bandcamp) and the money goes directly from the consumer to the seller via Paypal, thus you get it instantly, unlike iTunes, etc….
Bandcamp also offers the consumer the chance to stream the entire album before buying. What usually happens is most people listen to 2-3 songs and if they’ve stayed that long, they end up buying the album (they keep stats of what people do on your webpages, referrals, etc…)
In addition, some customers who are fans of your work, like to pay more, and Bandcamp gives them that option. I’ve had one customer pay $35 for my inMomentum album – which costs $5 on Bandcamp.
I could live – albeit not that well – off Audiojungle and Bandcamp alone. OK it’s not Themeforest levels, but…what is? 
(I also have music royalties, which isn’t ‘online’ earning, but it is passive income).