Free: Contests & Raffles.
bill of sale. if the guy will give you his DL #, great. otherwise just go with it!
With just a WA DL, you cannot tell whether a person is a prohibited purchaser. For example, if an illegal immigrant can get a WA DL, and I have no reason to think that they cannot, you could be selling to an alien without an alien firearms license. (There's some TX case, IIRC, where a guy was prosecuted for selling to an illegal alien.) Likewise, felons or those with DV records or protection orders against them could be prohibited persons and still have a WA DL. As a fellow "paranoid by nature" person, I like to require a CPL (or other good guy credentials such as Mil/LE*, current WAC membership, or other credential evidencing a background check has been performed, etc.) for all transactions. But beyond that, I do not keep records, because I am not an agent of the state for purposes of tracking down firearms used in crimes.Some people use the state firearms transfer record as an additional or substitute CYA, and if a person is not CPL'd and unwilling to undergo such procedures, they pass on the transaction. *NB - Mil/LE is not as surefire as a CPL or other credential evidencing a background check has been performed, but it gives me additional peace of mind that they are not an illegal alien and/or they have skin in the game as to not risk reckless behavior re: firearms.
Just because someone has a CPL does not mean they have good credentials......it means they had good credentials when they received the CPL.
*NB - Mil/LE is not as surefire as a CPL or other credential evidencing a background check has been performed