Financial questions that need an answer

i am trying to rent to own a trailer. the application was fine she told my 3 year old daughter we would be moving in soon, and then said there would just be a small credit check. we never signed anything consenting to a credit check, and was never asked for a fee for a credit check. is is lawfull to run a credit check with out written consent? there was nothing in the application, or in the fine print about it either.