"How much" is usually used to ask about the value of something. Example-how much are these shoes?, or how much does he weigh?. "How many" is usually used to ask about the quantity of something. Example-how many chickens are in the barn?, or how many times did she ask you?

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.