Garth Brooks said, "You aren't rich until you have something money can't buy." Well, you're on your way to rich, because you have today's GrammarPhile blog post, and it can't be bought with money!
Now, we like Garth Brooks, and we realize he wasn't talking about the GrammarPhile blog after all. But start here, and at least when you write about money, you'll make no mistakes. And that will save you money!
U.S. currency. If a number expressing an amount of money is spelled out, so are the words dollar(s) or cent(s); if numerals are used, they are accompanied by the symbol $ or ¢.
British currency. The basic unit of British currency is the pound, or pound sterling, for which the symbol is £. One-hundredth of a pound is a penny (plural pence), abbreviated as P (no period).
Other currencies. Most other currencies are handled in the same way as U.S. currency, with a decimal point between the main unit and subunits (e.g., EUR 10.75). When one or more letters are used, a space separates the letter(s) from the numeral.
Before adoption of the euro, monetary symbols included F (French franc), DM (deutsche mark), and Lit (Italian lira), among others.
Very large monetary amounts. Like other very large round numbers, sums of money may be expressed by a mixture of numerals and spelled-out numbers.