By conducting a social experiment, we investigate the appropriate marketing strategies to stimulate the purchase of environmentally friendly product (certified coffee). We contribute to the literature in the following three ways. First, our experimental scale is large, targeting more than 10,000 vending machines installed in the throughout Japan. Second, we distinguish the observations by the location of vending machines, such as open- and closed-spaces, and capture the actual purchase of certified coffee. Third, to rigorously identify the factors affecting the purchase of certified coffee, we use the prescreening regression approach to reduce the bias due to endogeneity and check the sensitivity of our results. The results show that the vending machines installed in the closed-space, such as factory, company and university, significantly increase the number of sales of certified coffee by providing the information regarding the certification system. Additionally, the information provision significantly increases the total sales of vending machines. These results suggest that the information provision in closed-space enhances users purchase behavior for the certified coffee and successfully acquires the new customers. In contrast, none of the interventions have significant impact on the vending machines installed in the open-space, such as station and shopping mall. Acknowledgement : This work was supported by JSPS KAKENHI Grant-in-Aid for Young Scientists (B) Number 15K21001 and Grant-in-Aid for Scientific Research on Innovative Areas Number 25101003.