If you haven’t already found your go-to summer sandal, consider this your sign. Flip-flops are totally having a moment right now, and even celebrities are rocking the trend. Katie Holmes recently stepped out in Archies Footwear Arch Support Flip-Flops in the perfect vibrant coral summer shade, and we need a pair ASAP. Though celeb-approved shoe styles are often way out of our price range, Holmes’ Archies start at just $40. Even better, they’re m…