Late last year into June of this year, Emma Stone switched things up by coloring her hair from her signature auburn to a platinum blond. But since then, she's returned back to the shade that made her famous. If you love the warm-toned look, but don't want to spend a lot of money going to a salon to get it, try Revlon Colorsilk Permanent Hair Color in Medium Auburn ($4) or Clairol Perfect 10 Permanent Hair Color in Auburn Flash ($12).
Keep in mind that Emma, a natural blond, likely has to go through a more involved process at the salon to achieve such a rich tone, so only try this color at home if your hair is a shade or two darker or lighter than the box color. And to maintain your new vibrant hue, try washing your hair less often, use cold water when possible, and refresh as needed with a color gloss.