Stop paying upfront

Lol I keep seeing on Reddit that people are just getting scammed so much man. It’s crazy. Why do you guys even pay these vendors upfront? Like do you know them? I see this so much it’s ridiculous man. They say they need all of the payment and then you wait a week and then it comes or doesn’t come? Like nah that’s crazy. A real vendor sends it and receives money after if you don’t know em. At least half and half man. It’s so sad