What is there to bring into blockchain in this kind of small and local business? Only the payment system of all your friend's gas stations? I don't think you need to undertake a large crypto project with your own developers and even start an IEO with this objective alone. When starting a project, always ask this question, what is new to this project? What problems that millions of people around the world are facing that this project of mine can solve? If this is your goal, I think you should instead open your gas stations for BTC, ETH, LTC, Waves, etc as payment.