I am travelling to USA tomorrow. Do I need US coins to pay at the toll?

Yes....

i suppose but im pretty sure they accept international money...OH WAIT!! TOLL! ue driving, oohhhh okay so yea u may want to go exchange

If you are renting a car at a rental company in the U.S. you will not have to pay the tolls at the airport. As far as paying tolls, that will depend on which part of the United States you are flying to. If it is New York City area, or really as a precaution the east coast of the United States, it is a good idea to have some money on you for the tolls. The bridges are usually another $3 or more to cross.

This site should help answer what tolls you will face on your drive and how much money to have on your trip. Enjoy your stay!

http://www.fhwa.dot.gov/ohim/tollpage.htm

any machine like tolls, phones, or vending can only take US coins. The only way to use foreign coins is to find someone that is willing to exchange them later.