Excise Tax: The 15% excise tax is a tax on the transfer of marijuana from growers to retailers (the dispensaries). You will not see this tax itemized on your receipt, but it will be passed down to the consumer in the form of higher retail costs. Currently the average price of an ouce of medical marijuana is $200. So the excise tax on an ounce would be roughly $30 on a $200 ounce, making the price $230/ounce before sales taxes.