An advance-fee scam is a kind of scam where someone might offer you something that seems too good to be true, like a large amount of money or a valuable item. They might tell you that you need to send money first in order to get the item or money. After you send the money, you never get the item or money and the scammer takes your money and disappears. They scam you because they know that if you send the money, you probably won't get it back. So always be careful, and never send money first if someone offers you something that seems too good to be true.