$2 primarily refers to banknotes, bills or coins, including:
Currency
Australian two dollar coin, which replaced Australian 2 dollar note Toonie, the Canadian two-dollar coin, which replaced Canadian two-dollar bill United States two-dollar bill, a current denomination of U.S. currency Hong Kong two-dollar coin, the third-highest denomination coin of the Hong Kong dollar New Zealand two-dollar coin, which replaced the two-dollar banknote
Other currencies with $2 banknotes, bills or coins are:
Bahamian dollar Barbadian dollar Belize dollar Bermudian dollar
Cook Islands dollar
Fijian dollar
Samoan tālā Singapore dollar Solomon Islands dollar
Tuvaluan dollar
Tongan paanga Argentine peso
Mexican peso Uruguayan peso Brazilian real
Other uses $2, a formal parameter in some programming languages