I was trying to sell an old laptop on Craigslist and got so confused trying to differentiate between legitimate and scam offers. For example, one guy from France offered to send me a money order and let me cash it before I sent out the computer, and was willing to pay more than I was asking. Another said he was happy to pay via Paypal if I just sent him my Paypal account ID. Were either of those legit? If not, how do the scams work?