Worst: Hummus
Unless you want to throw a party, there is no reason for you to buy the huge tubs of hummus from Costco. You should just get a small container from a regular grocery store to avoid wasting any food.
Worst: Printer Paper
If you do not print at home that often or are shopping for your office, you will get better deals on paper at the office supply store instead of Costco. Staples and other similar stores offer supplies and paper for very little money. You can get better discounts if you have coupons or attend a back-to-school sale!