The CCK is $30 and gives you a USB port. There are many midi interfaces available and multiple audio and combo ones also. Dropbox and iFunBox make transferring files easy. What I enjoy are the many high quality synths at give away prices that are availbable. Check out Animoog or Addictive definitely read up on Audiobus and Audioshare utility apps. Desktop music while not dead is on the endangered species list. Probably will be the final mix and master platform of choice for a few more years but for music creation it’s joining the typewriter.