Go to the customer service desk and buy a gift card. You can then shop without a membership to see if it is good for you.

Fruits and vegetables are really cheap at Costco. Cereal is retarded cheap. You get two huge bags of brand name cereal for like $6 compared to a small box at the supermarket for $4. Washing machine detergent is amazingly cheap at Costco.

The key to Costco is self control and not buying random stuff.