My answer to When do you need contracts for freelance services?
Answer by Ken Larson:
It does not take much effort to evolve a mutually agreed upon statement of work, terms, to include payment and limitation of liability. Once a standard, workable template is available it can be easily tailored to any freelancer business arrangement.
Without the above, the business risk is unacceptable. There are free templates at my web site in the “References” file at the right margin BOX. Download one and free free to protect yourself.