RAV4 starting problem

This is something my old car would do. I would buy a battery pack and leave it in the back of the car.

Most of the time when this problem arises suddenly, it's a dead or dying battery; you might have enough juice to light the lights, but not enough to turn the starter motor. Jump start the car properly; leave donor hooked up long enough to charge your battery, at least ten minutes. If your car starts, fine; the shop might have been right about the battery and it was low because you were cranking the starter too much. If it does not start, recheck your battery, it might now be dead..... If it's not the battery, it's probably the starter/solenoid or the ignition switch. Have the starter motor & solenoid checked. Jump the solenoid to eliminate the switch. If this works, it's the switch; if not, it's the starter.