#21 - It doesn't cost the earth
This Norwich drive-through carwash has a slogan which plays on the phrase "to cost the earth". The phrase's idiomatic meaning is 'to be very expensive', but it allows for a play on the word "cost", which can also mean 'have a negative effect on' or 'use up', as in "This project has already cost us lots of time and money", and "the earth" relating to the world, and particularly the environmental wellbeing of the planet. Consequently, the carwash company is simultaneously saying "Our service is inexpensive and environmentally-friendly" - two neat selling points in a four-word phrase.
Location: Drayton Road, Norwich, Norfolk, UK