Denver issues first licenses for legal retail marijuana sales Ahead of the day when Colorado residents aged 21 and older can buy marijuana for recreational use, the first batch of Denver businesses approved to sell the drug got their licenses Friday. Applause broke out and cameras whirred when the first license was issued from Denver's Department of Excise and Licenses. Recreational pot use by adults over 21 has been legal in Colorado for more than a year, but retail sales of the drug aren't allowed until 8 a.m. on Jan. 1. Retail sales of marijuana will be taxed at a rate of 25 percent in addition to Colorado's regular sales tax rate of 2.9 percent. State tax officials have estimated that the additional revenue would amount to $67 million per year, with $27.5 million already earmarked for new school construction. Individual marijuana sales will be limited to one ounce per person with a Colorado identification. Users from out of state can only buy up to a quarter-ounce. Resale is prohibited. Among those who have not allowed it are Colorado Springs and Greeley. Officials in cities like Fort Collins, Boulder and Aurora that they will wait to see how the first few weeks of legal sales pan out before issuing in their towns. About 160 retailers are still seeking licenses statewide.