Actually I just checked. The pizza slice is $2. I was thinking of the hotdog and soda combo, which is $1.50. Costco prices have always been consistent for me regardless of location. Even across two different states. Here's the full menu that I found online, although they don't usually have all of these options. I'm still bummed out that they stopped offering onions for the hotdogs.
A few years ago I read that Costco loses twenty million dollars per year on their rotisserie chickens. They sell them at a loss, and put them in the back of the store, hoping you'll buy some other shit while you're there.