There are many English idioms used on a regular bases by native speakers. Here are a few fairly common ones:
~to go bananas = to go crazy
"This annoying song on the radio is making me bananas!"
You could also say "driving me bananas"
~piece of cake = something that is easy
"The driving exam was a piece of cake."
~bring home the bacon = to earn money, usually in context of the household
"My wife brings home the bacon since she is a successful doctor."
~feeling under the weather = to feel ill/sick
"I am staying home from school today because I feel under the weather. I think I have the flu."
~on cloud nine = to be very happy
"After a successful first date, I was on cloud nine."
~put in one's two cents = to say one's opinion
"I put in my two cents at the business meeting."
~once in a blue moon = very rarely
"Sometimes we will have lunch together, but only once in a blue moon."
Hope that helps a bit!