Depends on how much you want to spend. I would suggest several Roland products. The RD600 which I have has 88 keys, probably under $1000 used. You may be able to get a used or demo Rd100 or RD150 for under $900. Yamaha has a real nice light weight 88 key piano, the P80, which I've seen for $899. All the ones I mentioned are professional and need a separate amp. I suppose it depends on her level of expertise. You might also try what I think is pretty cool, a Casio wk1630. 76 keys, lots of sounds and rythms, and a not bad piano sound, with built in speakers and amp, for $299. You might try Guitar Center, Musician's Friend, and even Sam's Club or BJ's wholesale. Good luck.
