For ever another point of a significant digit it's about another $250, to [.0] is about you know 30-40. To [.00] is about 250-300, and to [.000] is usually (for an actually a good one) is about $500 -$600 if not more. My AP Chem class got a couple(barely) for itself just this year, they were about $600 each for the [.000]

Dave