Want to cancel RV sale as wife lost job - how can we?

OK. You now have 7 pages of answers from the "I'm not a lawyer, but I play one on TV" crowd. Free legal advice is worth exactly what you pay for it - nothing. Different states have different laws. You stand to potentially lose $10,000 because the dealership took that RV off the market for some period of time. Talk to an attorney admitted to the bar in your state. You can bet that whatever you signed was written by their lawyer.