Feeling blue
Feeling sad
When pigs fly
Never
A pretty penny
Very expensive
Two peas in a pod
Both are the same
We're all in the same boat
We're all facing the same problem
Give the green light
permission to begin or go forward with something, such as a project, job, etc...
Kill 2 birds with 1 stone
Take care of two tasks at the same time.
Look like a million bucks
Look really good, happy, or healthy
Couch potato
Someone who is not very active and just likes to sit
Barking up the wrong tree
Asking the wrong person
Black sheep
A member of the family who doesn't have a good reputation
Bookworm
A person who studies or reads more than was usual or a lot.
Money doesn't grow on trees
Money isn't easy to earn
Who spilled the beans?
Who revealed the secret?
Slap on the wrist
Did not get a severe punishment
Golden opportunity
A good chance to do or succeed at something
Who let the cat out of the bag?
Who told the secret?
Wealth, or people who have money have a lot of power or influence
Bring home the bacon
Earn the income or the money for the family
An arm and a leg
Very expensive
Once in a blue moon
Very rarely
Ants in your pants
Always moving and squirming.
A dime a dozen
Very common
Butter someone up
Be extra nice to someone (usually for selfish reasons)
Hold your horses
Be patient