I've taken up piano recently and I'd like to not have to trudge up and down various and sundry hills in order to go to the music building if I want to practice in the evening. (As you may have noticed, I'm up after 3 most nights.) So, I was thinking of getting myself an inexpensive digital piano. My mom, a piano teacher (I quit her instruction at the age of 10), indicated that she'd be willing to contribute significantly to such a purchase. Any suggestions for a tentative budget of $500? I've heard good things about the Yamaha SP88(?), but I'm always open to more ideas. FWIW, I'll probably buy used.