It’s not that hard to make your own soda at home. You will need a flavored simple syrup (you can perfect any cola flavored one into a pepsi like flavor) and carbonated water. You can carbonate water by shaking water sealed in a plastic bottle while injecting CO2 into the bottle through a tube inserted into the top. Add the syrup to the water before you carbonate it. You can also get machines that will add the carbonation to the syrup for you but they can be expensive.