Magic Vocal Remover
Full user review
"Same as Audacity, except not free"
It works if you know what you're doing.
It's the exact same plugin that comes with Audacity (Which is and always will be free) packed into an EXE and sold for $25. I don't even think this is legal. Also, you rarely get high-quality results from this.
Don't but this. If you want instrumental songs, Google them. Try phrases like "instrumental," "karaoke," or "DDR/Dance Dance Revolution." I recommend a MediaFire crawler. If you absolutely cannot find it that way, use Audacity's plugin. You'll get the same result.