Unfortunately only US passport holders are currently able to visit United States.
United States is home to some of the biggest airports in the world. Starting with Atlanta, Dallas, Los Angeles, Chicago or New York. You can fin flights from any country in the world and thanks to its huge network of airports, you can arrive to almost any bigger city in United States. Thanks to its size, air travel is also the most common way to move within the country. Train network is not developed as well as in Europe or Japan and car or bus takes lot of time.
The currency is the United States dollar (USD). It is the most powerful currency in the world and serves as a major reserve currency and is used the most in international trade.The dollar derives its strength from the economic and political might of the USA. Its sign is $, and its currency code is USD. Due to the fact more other countries also use dollar, it is sometimes abbreviated as US$. Note that value of each dollar (US, Australian, Taiwan) is different.
The United States can be an expensive destination due to the high transportation and accommodation costs, but these costs can vary greatly from state to state with prices running highest on the coasts, in the national parks, and in Hawaii.
Despite ATMs being very common and 24/7, you can pay by a credit or debit card almost everywhere. Also if you are renting a car, prepare that the credit card will be required instead of standard payment card. Another US specific comes in a fact that chip + PIN cards are not so widespread as in Europe so you may be asked for a signature instead o a PIN in some cases.
Tip is almost necessity in USA, it’s a custom not to tip only if the service is really bad. The usual tip ranges between 10 and 20 % with a minimum o 1 – 2 USD.