The English meaning of "carros usados baratos" is "cheap used cars." "Carros" is the word for "cars," "usados" means "used" and "baratos" means "cheap." When these words are put together as a phrase it can also translate to "cheap secondhand cars."
This phrase is most commonly used when trying to sell pre-owned vehicles and advertising these vehicles for a reduced price. This phrase may also be seen on used car lots when the used car dealership has a large number of Spanish-speaking customers.
"Camion" is the Spanish word for "truck," so sometimes the phrase may switch between "carros" and "camion" when advertising cheap, used trucks.