Using data provided by state regulatory agencies and cannabis commissions, and when needed data from the research firm Headset, below are the states with the cheapest average cost per gram of dried cannabis flower. Oregon$3.33 per gram of dried flowerLegalized in 2014First cannabis store opened in October 2015Michigan$3.40 per gramLegalized in 2018First cannabis store opened in December 2019Massachusetts$4.15 per gramLegalized in 2016First cannabis store opened in November 2018Colorado$4.75 per gramLegalized in 2012First cannabis store opened in January 2014Maine$6.50 per gramLegalized in 2016First cannabis store opened in October 2020Ohio$6.55 per gramLegalized in 2023First cannabis store expected in late 2025Washington$7.12 per gramLegalized in 2012First cannabis store opened in July 2014Montana$7.15 per gramLegalized in 2020First cannabis store opened in January 2022