Expressão	Significa	Exemplo
to cost an arm and a leg	custar os olhos da cara	Rent in London costs an arm and a leg.
to be skint	estar duro, sem grana (coloquial)	I'm skint until payday.
to be over the moon	estar nas nuvens, feliz da vida	She was over the moon with the news.
to put your foot in it	pisar na bola, dar um fora	I really put my foot in it.
to have egg on your face	pagar mico, passar vergonha	He was left with egg on his face.
once in a blue moon	uma vez na vida, outra na morte	I take a taxi once in a blue moon.
not my cup of tea	não é a minha praia	Opera isn't really my cup of tea.
to be on the ball	estar ligado, ser esperto	Your new assistant is really on the ball.

Payday é o dia do pagamento. Skint é bem britânico; broke se entende em toda parte.