9 items in this article 4 items on sale! Photo-Illustration: The Strategist; Photo: Chris Gonz, Joe McKendry If you’re like us, you’ve probably wondered what everyday stuff famous people add to their carts — like hair spray or an electric toothbrush . We asked opera singer Joyce DiDonato — who stars in the new opera Innocence , opening tonight at the Met — about the Japanese incense, salt water nasal spray, and Spanish olive oil she can’t live without. After-work bath soak Saved View Want to be