MUSIC THEORY GAMES
To improve your piano student's theory skills, try the free theory drills at http://www.emusictheory.com/
WRITE YOUR OWN MUSIC
To give your student a way to write their own music, download Finale at http://www.finalemusic.com/notepad/ The demo version is free. The cheapest version is $10.
HOW TO BUY A PIANO
For help in buying a piano, try the advice at http://www.pianoworld.com/buypiano.htm The author is trying to sell his book but the free online advice is great.