Is Costco really cheaper?

I have started to ask myself this question since I have found the world of couponing.  I know for a fact that getting Cream of _________ Soups or Toothpaste for free or $0.25 definitely beats Costco prices.  But are there things I use a lot of that are actually cheaper at Costco?  Queen Bee Coupons did a recent blog post about this exact thing.  She actually went out and priced out things at Costco and put them on a spreadsheet as a reference for all of us!!!  Amazing!!  Click here is her blog post and the links to spreadsheet.  I know that I will definitely be referencing this when I am going grocery shopping since Costco is usually on my list of places to hit up.  :)