Visit 6 (4 Weeks Post-Quit). Participants will complete self-report questionnaires on a laptop computer; and expired CO and weight will be measured in a private room to ensure confidentiality. The visit 6 assessment will take approximately 50 minutes to complete. Upon return of the smartphones, participants will be compensated based on the percentage of completed random assessments. Participants who do not attend will be contacted by phone and/or mail to request that the phone be returned by mail (postage paid envelopes will be sent) or in-person at the next visit. When participants return the phone they will be compensated according to the compensation schedule described above. Participants randomized to the CM treatment will receive an additional payment if they self-report continuous abstinence from smoking since the quit date and have an expired CO level of ≤ 6 ppm. Participants who do not attend will be contacted by phone to obtain their self-reported smoking status.