In a service computing environment, Web service is maintained by various stakeholders including content providers, users and integration vendors of the service computing environment. These stakeholders make decisions about software/product license structure and billing system of services they are involved in. Service computing environment can be regarded as being provided and maintained as a synthesis of all these individual services. However, to make this service computing environment a sustainable one, validity of billing structure and fairness of cost burden among users need to be satisfactory from the users' perspective. The purpose of this study is to clarify, from a gaming experiment on the Internet, how users using a service computing environment will react to cost burden rules of certain services. In the experiment, highly public service operation model such as Language Grid was assumed and user behavior was investigated by combining incentive effect, its nature as a social investment and its nature as a Donationware where the payment of compensation for use is left to the user's judgement. As a result, it was clarified that users' behavior had a certain pattern with regards to interest and passivity towards donation and investment.