At some risk of sounding like a pessimist, I think you will find that the price of a digital piano is much more related to the quality of the action rather than the range of sounds. The range -- and realism -- of the sounds is basically a software or computer hardware problem, and both of those are very inexpensive. The action, on the other hand, is mechanical -- and to get one which feels even remotely like a real piano is going to cost real money.