Sometimes the Advance Fee Scam is compared to the 419 Nigerian scam.
The basic scam is one of the liar asking for an advance fee to obtain a larger amount of money or item of value.

One of the most well known Advance Fee scam is where an email is sent from an attorney or government official in a foreign country. They say they need someone to help move large amounts of money. The liar will ask you to pay a fee (via wire transfer) often to cover bribes or transfer fees for a percentage of the money. Many of these scams are actually well organized and are able to supply victims with official looking documents and working phone/fax numbers.
 There are estimates that these scam organizations are able to earn millions of dollars each year. The victims have not earned a penny. The organizations operate out of countries where the United States has no legal recourse.

In another version of the Advance Fee scam, the liar will state they can assist or guarantee you in getting a loan from a bank, investment, gift or even jewelry or cars. They will charge a fee for the service but after you pay they will dissapear. In some cases the liar will say they are working on it and may ask for additional fees until you finally stop sending them money.
Some will require you to sign nondisclosure or noncircumvention agreements as part of doing business. These scammers will use the agreements to threaten their victims with a civil suit if they report their losses to law enforcement. In some cases they can not be prosecuted as it can be difficult to prove they did not intend to deliver.