“No Purchase Necessary” rule or the Lottery Law applies to all U.S. sweepstakes and it bars Sponsors from requiring participants to purchase a product or pay a fee in order to enter a chance-based prize promotions, namely sweepstakes.
In order for a sweepstakes to be considered as a legal sweepstakes and not an illegal lottery, it must offer a free method of entry in order to meet the legal requirement to exclude consideration.
The no purchase necessary law is enforced by several supporting agencies, including the Federal Trade Commission (FTC), Federal Communications Commission (FCC) and United States Postal Service (USPS).
The enter for free method brands typically use is mail-in entry.
(See also: no purchase necessary laws, enter to win law)