Notice how we ask the price of something.
How much is this? How much are these? How much is that? How much are those?
To say prices, there is often a long way and a short way.
It’s four dollars and ninety-nine cents. It’s four ninety-nine.
We also use the plural for some currencies and the singular for others.
This is fifty dollars/euros/baht/yen/yuan/rupiah.
This is one thousand yen/won/lira/pesos.
The first time I realized that British English was much different from American English was the way they say numbers. They don’t say four dollars and fifty cents. They say four dollars fifty. Still understandable, but much different. In America we say “buck” as a dollar. “Hey, man….can I get a couple bucks?” That means you’re asking for two dollars.