The definition of a rule is  an official regulation, code of regulations or set practice. An example of a rule is that a red light means stop. An example of a rule is an employer demanding their employees arrive at 8am.
New injectors cost anywhere from $80-$120 apiece, making their replacement a somewhat pricey endeavor. There are three types of injector leaks-it can leak fuel into the manifold from the nozzle, it can leak fuel into the engine compartment from the fuel rail, and it can leak air (vacuum leak) from the manifold.
As far as getting the gas station to assist-- good luck! They will want you to try to prove you got your gas from there and it was their gas that caused the problem. Fuel injectors cost between $49 to $129 (roughly) apiece. Then you have to add in labor if someone else is doing the work. replacement fuel injector is about $78 - $91 each + shipping. Follow the link below. You need to install it yourself or find someone to install it for you.