The gas station is mostly for looks and starting money, but the majority of your income will be selling your excess fuels from the manage menu.
First you should buy an oil well and Fuel Tank. It will start making gasoline. Your excess can be sold in the manage menu. Once you can afford to buy a gas pump do so and then hire a worker. Focus on buying more storage and oil wells for faster production. Continue to sell your extra fuel until you can afford hydro-research. You can then sell all your gas equipment if you like as hydro pays more. You also do not have to upgrade to the next level machine unless you have no room, then it's worth it. Purchase hydrolizers, hydro pumps, and tanks until you can afford e-power research. At this point you are good enough to figure the rest out.