Sinking feeling

Referência: http://igetitcomics.com/2012/02/12/sinking-feeling/

Cost (somebody) an arm and a leg

Referência: http://igetitcomics.com/2012/02/26/cost-somebody-an-arm-and-a-leg/

High and dry

If you are left high and dry, you find yourself in a difficult situation without help or resources.

Example: When her husband walked out on her, Amanda was left high and dry with two kids to raise.

Down in the mouth

This expression is used when someone looks unhappy, discouraged
or depressed.

Example: "You look a bit down in the mouth. What's the matter?"

A fresh pair of eyes

We use the expression "A fresh pair of eyes" for a person who is brought in to examine something carefully. 

Example: As soon as we can get a fresh pair of eyes on this manuscript, we will find the last of the typos.

Hold your horses

http://igetitcomics.com/2012/03/11/hold-your-horses/

Green thumb

A person with natural gardening skills or has a natural talent for gardening

in UK its often called “having green fingers” or “being green fingered”

Well,  The Hulk has green fingers anyway 

http://igetitcomics.com/2012/03/30/green-thumb/