1989 Chevy Camaro Clicks but No Start?

Hey guys, going to college for my ASE certs for GM here. I have a 2.8 FI in my vehicle, just recently it left me at a gas station because it wouldn't stay on after turning it on, had to apply the gas and it turned on but wouldn't stay on. Brought it home on a trailer and parked it, friend said it sounded like it had a vacuum leak and wouldn't be sure unless it was connected to a computer to diagnose the issue. Since I've had it parked more less about a week now it won't turn on at all anymore, it has a click and the head lights become dim when I try starting it, but only clicking, no turn not even an attempt, exact mileage is unknown, but ran great when I first bought it. Thanks a lot in advance!