[Triple-X08]

exactly. check your battery connections, make sure they dont have any corrosion on them. if they are ok, then check the starter for amp draw. make sure it isnt too high.
should see about 150 amps out of it roughly. also you can disconnect the starter wire from the battery to the starter and check resistance in it. may be a solenoid problem or may be a wiring problem, or possible starter. also check your battery make sure it has good amperage on a load test. and check the cold cranking amps of it, make sure voltage is somewhere around 12.5 or so. if it goes down to like 7 volts when cranking then you have a problem.