The Costco Executive membership costs an additional $55 per year and members get 2% back annually. This means you’d have to spend $2,750 per year in order for the Executive membership to be worth it (or $229 per month).The “Costco effect” is when someone goes into the store to buy groceries and ends up buying other items because they are a good deal.his means you’d have to spend $2,750 per year in order for the Executive membership to be worth it (or $229 per month). The “Costco effect” is when someone goes into the store to buy groceries and ends up buying other items because they are a good deal.