Always quote prices in US Dollars, unless you’re specifically referring to a regional cost, or a product/service only available in a particular region.

Use the $ symbol: $20.

Don’t use decimals unless cents are included, e.g. $20.50 but not $20.00.

Don’t use ‘$0.xxm’ for amounts less than $1 million.

Write out ‘cents’ in full: ‘it costs 8 cents per minute to call the support line’.