What is the advantage of a postal money order vs certified check? I am wondering because I am selling my motorcycle and a guy is coming up this weekend with a certified check. It got me to wondering why everyone always asks for a postal money order for guns. I am guilty of doing this myself....and I don't even know the advantage of it!! I've bought used guns and sent a postal money order, no problem....I just don't know why we do it. Anybody know???