Whenever I present my course Costco memberships always come up. Are they worth it? I always say you need to figure out if you save more money than the membership fee. We get ours as a Christmas gift each year from my husband's parents. Anyways, I learned today that membership did have it's benefits! I had to blog about it, in case any of you have lost receipts and need to find them!We bought a Costco truck battery at the end of 2009 and last month it died. Costco batteries have one of the best guarantees out there at 3 years. When our battery died I went to my handy dandy file cabinet where all my receipts are. Under B for batteries I didn't find a Costco receipt! I began a furious search through a year's worth of monthly envelope files, with no luck! I was distressed as the battery would be 100% replaced, which was $95 plus tax. I basically lost $100. We bought a new battery and I continued my search. Finally, the other day we were at Costco and I got an idea. I asked the cashier if they could search my Costco American Express card and find this purchase? She said, "No problem!" Today, I went in with the battery and viola, a $106 cash card! This time membership did have it's privileges!