Red Karaoke features an “easy-to-use interface” and “professional quality” backing music. You can even adjust the key of the music to match your voice. You get to enjoy two popular songs or so for free, then have to pay a $7 monthly or $40 annual subscription fee. (Android and iOS)
Karaoke Anywhere has a “slightly pedestrian design,” but it offers some nifty vocal effects, including reverb and echo. After using your free credits, you pay $2 a song or $10 monthly. (Android and iOS)
Smule’s Sing! Karaoke “offers a more sophisticated karaoke experience,” including allowing you to sing live with someone halfway across the globe. The app can also score your note accuracy, turning singing into a game. You pay $1 a song or can subscribe to the service for $5 monthly or $25 annually. (Android and iOS)
Source: The New York Times