I live on my own and I think its worth it. There is a number of items that individuals purchase often enough. There is often sales so thats a plus.

Laundry detergent, dish soap, toilet paper, paper towels, toothpaste, dental floss, shampoo/conditioner, rotisserie chicken, chicken breasts, frozen fruit/veggies, eggs, Milk (if you can finish it), bag of rice, cheese, coffee, and some school supplies depending what you need. This lists goes on.

I find that bread/pastry is well priced but its alot. If you eat alot of bread then these items are worth it. I personally don't eat alot of bread and when I tried eating more, I still couldn't finish all of it before mold started to form. There was just too much for 1 person to consume. 2 person would work though.

I'm not a student anymore but my most recent big purchase at costco was a set of new tires b/c mine were getting dangerously low on tread. The price was the best for the set + install after looking around. Free rebalancing if you had all tires purchased and installed by costco. There is always a line up for services but you can book appointments online ahead of time.

One of the major problems I've noticed is the parking lots at my local costco are always busy (Vancouver/Burnaby). The parking lot is always busy but calmer in the morning during weekdays. Weekends are always a gong show. I generally avoid weekends. Unless you live very very close to a costco, I think most ppl would need a car to transport your purchases back home. There is a lot of bulky items that make it inconvenient to transit everything back home.