I am in Ming-Tzu's shop and it won't let me buy anything. He just keeps telling me to give him my number. Please help me before I throw my PC through the window.

Man i can't remember I havent played thia game in ages but i guess the number is on your card when you open the inventory and you use the arrow keys to rotate if no

chek the walkthoruugh of the game that will be more specific

Thats the thing, it does not show in my inventory. When I collect stones it appears on screen but I can not find it anywhere else.

You just approach the thingy at the front desk and click. You don't even need to go through your inventory. It's next to the character and should say "use" instead of "talk."