Surge Cola draws a blank with me. I do remember Jolt, and a mini-craze for Canfield's Chocolate Soda that I participated in. It wasn't remotely chocolate, more like a cream soda variant, but it wasn't bad.
All the following are best value anywhere by a decent margin. All are off the top of my head. Southern California...
Milk
Gasoline
Rotisserie Chicken
Generic zyrtec
Kirkland Dishwasher pods
Kirkland AAA/AA Batteries
Car tires
Car Batteries
Kirkland Vitamin D3
Hotdog/Burger Buns
Most Furniture
Kirkland Toilet paper/Paper Towels
Vacation Packages
Edit: OMG, I almost forgot - Pumpkin Pies!!!!
I'm sure I'm missing a bunch of other stuff. And there's tons of things that are good prices but will commonly be beat at other places. e.g. Coffee or Soda
Not so great deals:
Meats
plants
Desserts
Premade foods
TV are decent value but all mid range.
Computers are okay but probably a better deal at Best Buy when freq on sale
CHEESE Mark. On a cost to quality ratio, CostCo cheese is the best by a wide wide margin.