I was going to say what Kat said. The squat rack has safety pins you can set at a height to catch the barbell for bench if you want to go heavy. If you get stuck at the bottom, you can roll the bar along the pins (down toward your hips) until you can sit up...practice with just the empty bar to get the height correct and to give yourself confidence. It rolls easily on the pins so isn't a big deal.
Ditto for squats, set the pins just below the lowest level you want to squat, and practice with the empty bar: pretend you're stuck in the bottom, and just sit a little deeper to let the pins take the weight off your back, or simulate doing the old "good morning squat" where you lose it forward, and just duck out from underneath it. We're talking 2" or less, so it's really not a big deal.
For deadlifts you don't need a spotter, since you can just drop it if you get in trouble. If the gym has rubber bumper plates those are always a little quieter and less rough on the barbell than dropping it with metal plates on, but unless it's a crap bar, it won't really hurt it on a deadlift if you drop it.
For overhead lifts, it's nice to have bumper plates (the rubber ones like they use in olympic weightlifting) so that if you get in trouble, you can just dump it forward or backward and just move out of the way. If the gym has a weightlifting platform, usually these are wood in the middle with rubber mats where the plates would be on the barbell, that is what it is designed for, to absord the shock of the barbell being dropped onto the rubber mats. Dumbbells are usually okay to drop if needed...just try to drop them on some type of rubber mat if possible and control whatever you drop so it doesn't bounce into a mirror or another gym-goer.
My best advice is just to practice with light weights, which will give you confidence when you work up to using heavier weights, and start with higher reps for your working sets...by the time you work your way down from say, 8-10 reps that are heavy for you, to doing heavy triples, doubles or singles, you'll know how to handle the equipment and have confidence in either dumping the implement or using the safety pins in a squat rack. Definitely don't let lack of a spotter stop you from lifting!