How much is used for uncountable things, eg, how much water?
How many is used for countable things, eg, how many fingers?
Notice that money is uncountable: How much money do you have? If you talk about the units, dollars, euros, etc, then yes, they are countable.
People are countable. How many people? This is different in Spanish for example.
I hope this helps.
Regards,
Simon.