I agree, only go to Sams/Costco if you know what things are supposed to cost.
They have deals on big containers of stuff but if you don't use stuff before it
goes bad it is not a bargain.
I buy non perishables and things I use a lot of.
They also have great deals on close out items but that is not predictable and
it is easy to get a great deal on something you will never use if you get
caught up in the moment.