For me i find a good trustworthy supplier and stick with them if i but online and i keep my cash in a safe but for only bill money goes in the Bank i usually buy local and pay cash as well as going in the gas station to pay for gas because of skimmers and so far i haven't been ripped off I don't do Amazon so much only if I have to
amazon is perfectly safe if you are careful..
i've seen a lot of fake sites. the scammers fake a number of popular auto parts sites as well that i've used.
edit : i recently had to cancel my card over almost the same thing. i caught it before payment went through. i no longer leave my info on amazon.