This is a plug for their travel service. I recently booked a 7-day stay in Hawaii (on the big Island) for two. Total cost for airfare, rental car and hotel was under $2000. We also signed up for the King Kamehameha Luau. It was cheaper than anything we could find on any of the travel sites. Plus I have access to special discounted hotels through the military but even still, Costco was cheaper.
They offer a lot of discount online services for members including car insurance. I remember getting an online quote from the company on their site and it was about $30 cheaper per month than my current insurance.
Others have saved big money through their car purchasing program.