I mostly just buy nonperishable items from Costco. Last time I bought nuts, for example, most of them went rancid before I could finish them.

Nonperishable items:

Dishwasher liquid; Bleach; Toilet Paper; Paper Towels; Laundry Detergent; Flea meds for cat; Trash bags; Wax Paper; Picnic supplies (paper plates, cutlery, napkins, cups); books (discounted); car detailing products (shop rags, wax); Brita filters; Clothing - sometimes you can find things - I got thermal underwear there - loved it; gasoline; you can also get tires!; lower prices on eyeglasses;


Food Items:

Cheese ('cuz you can cut that 2 LB block in half and freeze some); Butter (ditto); Cream (If I'm going to be making ice cream); Cream cheese (if I'm going to be making cheesecake); Eggs (cuz I eat a lot of 'em); Coconut Oil; Avocado Oil; Almond Flour - if you can use the quantity; Sometimes veggies - I like those mini sweet peppers; mushrooms; onions; Flowers; Lemon Juice ("Italian Volcano") - comes in a liter sized bottle - keep in the fridge; Vinegar...