You need money to construct the station, and it isn't going to be cheap to dig and place the tanks, create the bays, and set up the building. Unless you plan to open as an independent retailer you will need to pay one of the big oil companies a hefty franchise fee to use their corporate logo and brand name. The fact that you want to go terror-free is cool because that tells me right away that you're not interested in dealing with companies like Shell or Exxon. But you have to be careful and really do your research before you jump in. Discount gas retailers like Getgo, Kroger, and Walmart are planning to expand their tentacles into the market, and these companies are known for selling their product slightly below market price to increase traffic and drive up massive sales. In many cases, it is a strategy that works because people will go where they can get the cheapest gas, and once they are outside that Walmart store pumping gas you KNOW most of them are going to go inside the store to buy something---and that's the whole idea. For the smaller independent retailer this could mean trouble because you may not be able to compete against them and make a profit if they open up a set-up near yours.
The other thing you have to consider is the volatility of the petrochemicals industry. Prices are slowly going higher and higher, and the profit margins for retailers in this business are already quite thin. While doing your research you will find that most of the profit that gas stations make doesn't actually come from gasoline sales but from food and other items that customers buy inside the store while they are filling up their tanks, so it is a good idea to have a convenience store type of set-up as well. And, in terms on location, you don't want to choose property just because you like it or because it is affordable. True, it needs to be both those things but the most important consideration is that it is in an area that has enough traffic to generate a lot of sales.
If you have never worked in the industry I strongly suggest that you talk to people who do before investing your money.