Inclusion Criteria:  Sufficient English fluency to complete study procedures At least 21 years of age U.S. resident of any state currently smokes at least 5 cigarettes per day has an email address has a mailing address at which they can receive packages owns an Internet-connected Apple iPhone or Android smartphone that is compatible with QuitBet willing to deposit $30 via PayPal or a credit card willing to receive financial incentives earned during QuitBet via PayPal or in a paper check sent by mail