$24.99 thru iTunes.
I just made a rough track using it with a stereo drum loop, live electric guitar, bass, and vocal. I used its pretty awesome EQ and compressor, noise gate and reverb. I used Amplitube for iPad for the guitar. I sang right into the iPad mic and actually got a usable scratch track!
I exported the mix at 24bit 44hz to DropBox.
I also bought iPad Drumagog for 19.95 to test out in it.
This is a really nice piece of software. $24.99! It is blowing my mind.