You can get some decent deals on tires there but keep in mind you'll need to get serviced at a Costco if you want to use those benefits. If you're someone that has to drive far to get to your Costco, might not be worth it for you.
Most basic food items, like rice, other grains, condiments, meats like chicken breasts, bananas, - make a list of things you typically use and eat. You can probably score them at Costco. Do the same with what you use to clean, soaps, shampoo, conditioner, vitamins, q-tips.
If you're just a single person household, it probably won't make sense for you to get a membership. 2 people minimum, in my opinion.