1.Be in hot water

Meaning:
Be in trouble
Example:
He found himself in hot water over his speech about immigration.

2.It cost an arm and a leg

3.It’s in the bag

Meaning:
It’s a certainty
example:
The election is in the bag unless the voters find out about my past.

4.Get cold feet

Meaning:
Be nervous
example:
I'm worried she may be getting cold feet about our trip to Patagonia.

5. A rip-off

Meaning:
Too expensive
Example:
Mobile phones can be a real rip-off if you're not careful.