Don't try to open up your battery. If you still have the original battery then there should be a clear circle on the top and a label next to it that indicates how charged the battery is according the the color. If you have a different battery, take it to any major autoparts store (Pepboys, Napa, Kragen, etc.) and they will test your battery for free.Now if you keep draining batteries then it is more than likely the alternator that needs to be replaced.Make sure there is no rust on the battery wires. If there is rust, mix lukewarm water with some baking soda and scrub the wires clean using whatever brush you got laying around. If that doesn't work then you'll need some new battery wires.There could be a number of things wrong with the car depending on how the car sounds when you try to start it.Clicking noises probably means you need a new starter.If the engine turns but it doesn't start, then it could be a clogged fuel filter, a bad fuel pump, or something electrical.www.partsamerica.com is a good website to see how much your replacement parts cost. All you have to factor in is the cost of labor which differs from mechanic to mechanic.