What is worth of a 2000 us liberty gold dollar coin with lady and baby on front and eagle on back?

It sounds like a Sacagawea dollar. If it is, it is not true gold. It's a composite of different metals: 77% copper, 12% zinc, 7% manganese, 4% nickel, bonded to a core of pure copper. Though you did not state the coin's mint mark of P, D, or S, generally its value in a mint state of 64 (MS64) is worth: $3-$5.