We have been exploring the use of Electric Vehicles (EVs) as a new method for utilizing surplus electricity generated by renewable energy sources. In our method, surplus electricity in households with photovoltaic panels is stored in EV batteries and then sold to other EVs at EV stations located at workplaces or commercial facilities during routine travel. Moreover, we have considered the method of notifying the electricity prices to the EV users prior to the departing from home, for preventing many EVs from concentrating at conveniently located EV stations. However, since electricity prices fluctuate due to changes in the balance between supply and demand at each EV station, a difference arises between the pre-notified price and the actual price. Therefore, in this paper, we conduct simulation experiments to clarify how the electricity price fluctuations affect electricity trading among EVs.