Getting screwed over on a payment for a parts purchase?

I was thinking maybe purchased like a cheap $7 item and everything went fine and that was more or less the bait... Around $100 is basically my threshold for online from a private party.. I can live losing that but getting into 500 or $1,000 from somebody I don't know I can't afford that..
I held my breath as I sent $$$$.$$ for my '76 Duster. Then the shipper had problems. Was I nervous? you bet! But the seller was outstanding and the car arrived and all the stories were legit. I don't advise it. But I was fortunate to have a honest person at the other end ! About 1500 miles away from me at the other end ... LOL