Never wire money to the other party • If you do make a deal with someone far away, don't pay through Western Union or a similar service. "Anyone who asks you to do so is a scammer," Craigslist warned.
Craigslist does not guarantee transactions • It also doesn't "certify" buyers or sellers, or protect payments in any way. If someone says Craigslist will do so, they're probably trying to deceive you. Some scammers will send an official-looking email, appearing to come from Craigslist, saying that the site will guarantee the transaction. Don't believe it.
Watch out for overpayments • An all-too-common ruse is for sellers to be sent a "bank check" for more than the selling price, with a request for the balance to be returned. If this happens, you can be sure the check is a fake.
See things for yourself • Don't rent an apartment or house without viewing the inside, and don't buy something expensive without seeing it with your own eyes. If the other party balks, said Craigslist, "in all likelihood that housing unit is not actually for rent and that cheap item does not exist."
Los Angeles Times