Expresión	Significa	Ejemplo
to cost an arm and a leg	costar un ojo de la cara	Rent in London costs an arm and a leg.
to be skint	estar sin blanca (coloquial)	I'm skint until payday.
to be over the moon	estar contentísimo	She was over the moon with the news.
to put your foot in it	meter la pata	I really put my foot in it.
to have egg on your face	quedar en ridículo	He was left with egg on his face.
once in a blue moon	muy de vez en cuando	I take a taxi once in a blue moon.
not my cup of tea	no es lo mío	Opera isn't really my cup of tea.
to be on the ball	estar al loro, ser muy espabilado	Your new assistant is really on the ball.

Payday es el día de cobro. Skint es muy británico; broke se entiende en todas partes.