This Walgreen's is incredibly convenient if you're staying on the strip in the Venetian, the Wynn, Treasure Island, or Mirage. It's located under the Canal Shops at the Palazzo and can serve any and all of your sundries needs.
This is definitely the place to stock up on your needs for your weekend in Vegas so you don't have to pay a premium to buy them from the hotel when you need them. Sunscreen, bottled water (stay hydrated! It's a desert out there!), Advil... you name it, they've got it.
Convenient and affordable. Good stuff.