Think of it like a tank of water how much the tank can hold is your mah, then there's hose connected to it, the bigger the c rating the more water will shoot it. And I wouldn't say cheaper batteries are less quality.. My reedy 2s lipos are 4100 mah and 65c I think and are like 80$ and the turnigy nano techs have more mah and discarge rate and and are cheaper and have lasted way longer