Can you please help a Newbie?

I have a document that has a dropdown list of names. The cell next to it needs a doller amount that corrosponds to the individual names. Can this second cell be filled automatically? It would look something like this:

Joe 150.23
Bob 75.89

I'm sure this is unbelievably simple, and I appologize if it has been answered before. This is my first post here so if I have not provided enough information please let me know.