Stone, I recommend using Alabaster or Soapstone to begin with. They are two of the softer types of stone and carve easier than the harder types.
Alabaster can be breath taking when finished.
A banker , or work bench, should be strong enough to hold the weight of the stone and be stable enough to take the abuse of the pushing and pounding of stone carving. Sand bags can be made from the cut off legs of an old pair of jeans, filled with sand, and tied off. Sand bags hold your work in place while you are carving and polishing. Chisels and a hammer to remove larger amounts of stone and to shape the stone. Files and or rasps with which you will be filing and smoothing the stone.