There are many pros and a few cons to shopping at Costco.  I posted a few months ago about the perks of having the Costco TrueEarnings American Express Card, read more about it here.  Another perk that goes with having the Costco American Express card and the Executive membership is the 2% annual reward you earn.
You earn 2% back on every purchase you make at Costco on top of the awesome cash back rewards you earn if you use your Costco American Express card.  What a lot of people don’t realize is you can take your rewards certificate to any Costco and cash it!  You don’t have to spend it all at Costco, which most people do, you can put money in your pocket or savings account!