Money doesn't grow here.
Money doesn't grow on trees.
Something that happens very, very quickly.
Lightning fast.
Someone who likes to read a lot.
A bookworm.
A very good opportunity.
A golden opportunity.
It costs peanuts.
It is very cheap.
To look and feel great.
Like a million bucks.
To be just a little bit sick.
Feeling under the weather.
To reveal a secret.
Let the cat out of the bag.
To do exceptionally well on something.
To pass with flying colours.
It's the food you bring home when you earn a living.
You bring home the bacon.
Do something rather than just talk about it.
Put your money where your mouth is.
To feel very happy.
On cloud nine.
To be very busy.
Busy as a bee.
Not clearly right or wrong.
A grey area.
If something sounds good but is unrealistic, where is there a pie?
In the sky.
Money does this to people's pockets who like to spend it.
It burns a hole in their pockets.
A person who is a friend only when things are going well.
A fair-weather friend.
Someone stubborn and inflexible.
Stubborn as a mule.
To get approval for something.
Green light.
That's just how things are.
That's the way the cookie crumbles.
To owe someone money or a favour.
To be in their debt.
When it is suspiciously quiet while expecting chaos.
The calm before the storm.
A shy or quiet person.
A dark horse.
Something that happens rarely.
Once in a blue moon.
To have more important things to do.
Have bigger fish to fry.