The purpose of this study is to examine the effectiveness of an internet-based contingency management program for smoking cessation in persons who are homeless. Thirty homeless smokers will be enrolled in the study. Participants will receive payment based on their own low carbon monoxide readings, which indicate being quit from smoking. Participants will be prescribed nicotine replacement (patches and either gum or lozenge)and bupropion. All participants will receive a four sessions of smoking cessation counseling, and will be trained to perform carbon monoxide monitoring with a device provided by the study. They will also be provided with a mobile phone equipped with a video camera, and will use this equipment at home to monitor their carbon monoxide . Participants will record videos of themselves taking a carbon monoxide reading and displaying the results, and will upload the videos to a secured website that is only accessible by the research team members and the participant. Payment will be based on providing carbon monoxide readings that indicate abstinence.

The study is designed to address the following aims:

Specific Aim 1: To evaluate whether it is feasible to use internet-based contingency management for helping smokers who are homeless stop smoking.

Specific Aim 2: To evaluate how effective internet-based contingency managementis on decreasing smoking in smokers who are homeless.

Inclusion Criteria:

• must be a Veteran who is eligible for care within the VA system;
• must be currently homeless or have been homeless more than twice in the past year period;
• must have current smoking status of at least 10 cigarettes per day for at least 1 year (verified with breath carbon monoxidemeasurement);
• must be aged 18 to 70;
• must be English speaker

Exclusion Criteria:

• Pregnancy;
• Any substance use disorder in any of the following drug categories: opioids, cocaine, alcohol, sedatives, stimulants, hallucinogens, or drugs categorized as "other" per the Structured Clinical Interview for Diagnostic and Statistical Manual-IV.
• Urine drug screen results positive for cocaine, amphetamines, stimulants, opioids, or hallucinogens;
• Not stable on medications for the study period;
• Use of any other forms of nicotine such as cigars, pipes, or chewing tobacco;
• Participants may be excluded if they have a seizure disorder, uncontrolled diabetes or an eating disorder;
• Prior history of hepatitis or cirrhosis; current hepatitis or cirrhosis
• Score less than 80 on Kaufman Brief Intelligence Test