I would probably use pesos or maybe Euros
Grams or milligrams would be appropriate units to measure the weight of a five peso coin.
Newtons
A newton - or a millinewton.
The Mexican currency is the Peso.
Milligram: to measure its mass.
The Philippine accountant considers peso as the common unit of measure for all business transactions. There are rare times that the US dollar is also used.
Yes
It means "one peso." The peso is a unit of currency.
centigrams
Monetary unit: Colombian Peso
division
You would use the unit of measure called "kilograms" to measure the mass of an elephant.