You still need a microphone to play it, and yes, you'll have to pay for one if you don't already have it. But it appears SingStar, the venerable PlayStation karaoke title, is going free-to-play, according to a message screen popping up now.
"The complete SingStar experience will be available as a free download very soon!" says the screen, encountered in the free SingStar viewer. The whole thing means to say the service has been discontinued but will be reborn later.
PSNStores.com notes that "complete SingStar experience" likely means freeing users from the need to put a disc in the tray to play content purchased from the game's online store. Moving the title to an a la carte, semi-free-to-play experience probably is smart. You still need to buy a controller to play it, so keep that in mind.