That really depends on what you are looking for. If you want markets with handicrafts and souvenirs that you can bargain for, you can hit Coral Negro Flea Market in the hotel zone or Market 28 downtown. If you are looking for groceries and supplies for the week like sunscreen, head to Walmart downtown. If you want high end luxury clothes, jewelry, perfumes etc., go to Plaza Kukulcan or Plaza La Isla. For a regular ole, American style mall, come downtown to Plaza Las Americas. Happy spending!
Is Costco any good? I have a membership, so maybe I should use it. Also, where is the best/cheapest place to buy liquor and beer? Walmart?
Costco is great and is definitely a good place to buy liquor, beer etc.. Good selection and cheap prices. Your membership will be welcomed there no troubles.