Non food cost big bucks!

I am reading a book Cut your Bills in Half I got it at the second hand store.
Grocery stores mark up nonfood items to compensate for low food prices. They suggest buying these at the discount store.
Here is the list:
Brushes, Paper napkins, Shampoo, dish detergent, tissue, garbage bags,
toilet paper, Laundry soap and toothpaste.

What are some thing's you've found cheaper at the discount store?
Thanks