There are a number of specific federal and sate laws and regulations that you will need to comply with in selling cigarettes online, including the Prevent All Cigarette Trafficking Act (PACT), an act that specifically regulates internet sales of cigarettes. One feature of this Act is to ensure that all state cigarette taxes are paid, which can be somewhat complicated. Due to the potential penalties and complexity involved with selling cigarettes online, I highly recommend that you find an experienced attorney to help you set this business up in a compliant manner.
This advice is for INFORMATIONAL PURPOSES only and should not be relied upon as legal advice. No attorney-client relationship shall be formed as a result of the answer above.