Free: Contests & Raffles.
You do not have to go to an FFL. If you just want to cover your a$$ from any dirtbags then instead of a bill of sale you can go to the Dept of Licensing web site and get a firearms private disposition/transfer form and fill it out with the purchaser of your firearm. You don't have to turn this form in just keep it for your records but if you really want to cover yourself there is an address that you can mail that form to. The form is for handguns but you can easily use it for rifles. Here is the link. http://www.dol.wa.gov/forms/652004.pdf