From the Heartland Institute:

A 2017 Policy Study by the R Street Institute analyzed a smaller number of Medicaid recipients switching from combustible cigarettes to e-cigarettes. Associate Fellow Richard B. Belzer used a sample size of “1% of smokers [within] demographic groups permanently” switching. Using this analysis, Belzer estimates Medicaid savings “will be approximately $2.8 billion per 1 percent of enrollees” over the next 25 years.