A view of the screen of a ZaZZZ vending machine that contains cannabis flower, hemp-oil energy drinks, and other merchandise at Seattle Caregivers, a medical marijuana dispensary, in Seattle, Washington February 3, 2015. Vending machines selling medical marijuana opened for business in Seattle on Tuesday, in what the company providing them billed as a first-in-the-state innovation that it expects to expand to other cities and states where pot is legal as medicine. (Photo by David Ryder/Reuters)

Lynyrd Puyat uses a ZaZZZ vending machine to purchase one gram of the Girl Scout Cookies strain of marijuana for $15 at Seattle Caregivers, a medical marijuana dispensary, in Seattle, Washington February 3, 2015. (Photo by David Ryder/Reuters)

Lynyrd Puyat uses a ZaZZZ vending machine to purchase one gram of the Girl Scout Cookies strain of marijuana for $15 at Seattle Caregivers, a medical marijuana dispensary, in Seattle, Washington February 3, 2015. (Photo by David Ryder/Reuters)

Lynyrd Puyat shows one gram of the Girl Scout Cookies strain of marijuana that he purchased for $15 using a ZaZZZ vending machine at Seattle Caregivers, a medical marijuana dispensary, in Seattle, Washington February 3, 2015. (Photo by David Ryder/Reuters)

Stephen Shearin demonstrates the use of a ZaZZZ vending machine that contains cannabis flower, hemp-oil energy drinks, and other merchandise at Seattle Caregivers, a medical marijuana dispensary, in Seattle, Washington February 3, 2015. (Photo by David Ryder/Reuters)

Stephen Shearin demonstrates the use of a ZaZZZ vending machine that contains cannabis flower, hemp-oil energy drinks, and other merchandise at Seattle Caregivers, a medical marijuana dispensary, in Seattle, Washington February 3, 2015. (Photo by David Ryder/Reuters)

Stephen Shearin demonstrates the use of a ZaZZZ vending machine that contains cannabis flower, hemp-oil energy drinks, and other merchandise at Seattle Caregivers, a medical marijuana dispensary, in Seattle, Washington February 3, 2015. (Photo by David Ryder/Reuters)

Stephen Shearin inserts a note as he demonstrates the use of a ZaZZZ vending machine that contains cannabis flower, hemp-oil energy drinks, and other merchandise at Seattle Caregivers, a medical marijuana dispensary, in Seattle, Washington February 3, 2015. (Photo by David Ryder/Reuters)

Stephen Shearin demonstrates the use of a ZaZZZ vending machine that contains cannabis flower, hemp-oil energy drinks, and other merchandise at Seattle Caregivers, a medical marijuana dispensary, in Seattle, Washington February 3, 2015. (Photo by David Ryder/Reuters)

Stephen Shearin retrieves a can of Canna Energy Mango as he demonstrates the use of a ZaZZZ vending machine that contains cannabis flower, hemp-oil energy drinks, and other merchandise at Seattle Caregivers, a medical marijuana dispensary, in Seattle, Washington February 3, 2015. (Photo by David Ryder/Reuters)

A view of the screen of a ZaZZZ vending machine that contains cannabis flower, hemp-oil energy drinks, and other merchandise at Seattle Caregivers, a medical marijuana dispensary, in Seattle, Washington February 3, 2015. (Photo by David Ryder/Reuters)

A view of a ZaZZZ vending machine that contains cannabis flower, hemp-oil energy drinks, and other merchandise at Seattle Caregivers, a medical marijuana dispensary, in Seattle, Washington February 3, 2015. (Photo by David Ryder/Reuters)

A view of ZaZZZ vending machines that contain cannabis flower, hemp-oil energy drinks, and other merchandise at Seattle Caregivers, a medical marijuana dispensary, in Seattle, Washington February 3, 2015. (Photo by David Ryder/Reuters)