9 items in this article 1 item on sale! Photo-Illustration: The Strategist; Photos: Nick Delisi, Joe McKendry If you’re like us, you’ve probably wondered what everyday stuff famous people add to their carts — like mascara or a sleep mask . We asked musician Rostam Batmanglij — who just released a new single and music video, “ Back of a Truck ,” from his forthcoming album, American Stories — about the toothpaste, noise-canceling headphones, and ankle socks he can’t live without. The non-