When you turn the key all you hear is a clicking noise and some say that its the starter but you don't know?

If the voltage level of the battery is low, turning the key to "Start" can cause a further voltage drop and you'll hear the click. Sometimes the low voltage condition will be such that the starter is engaged, drops voltage below a threshold, the solenoid disengages because of low voltage condition then the voltage comes back up enough to re-engage the solenoid and it clicks again. In either case, if you have a volt-meter check the voltage of the battery while someone attempts to start the engine. If the voltage stays anywhere near 12 Volts, check both battery terminal connections. If either is dirty you may just need to clean the contacts. If the battery voltage is down near 7 or 8 Volts when you try to start the vehicle your battery voltage is too low to do much good. The battery COULD be bad or the alternator may just not be charging. Don't just replace the battery until you are able to determine if it's a battery or alternator problem. With the same volt meter, check the battery voltage when the engine is running. The alternator SHOULD bring the battery voltage up to 13.5 volts (or near enough) and if it doesn't, you probably have a charging problem. In either case, have a reputable parts store, like Checker Auto, Kragen Auto, Auto Zone or Pep Boys check the charging system and the battery to find out what's wrong. In some cases the starter can be faulty and drawing too much current but they can check that too.