If anyone knows about preppy Ralph Lauren-inspired dressing, it's Hilary Duff. With her latest polo sweater style, Duff nailed the trend that Jennifer Garner, Gwyneth Paltrow and other rich moms are obsessed with lately. We found her East Coast look for only $20 on Amazon, and the budget-friendly alternative is just as cozy, versatile and classy. Plus, it could totally pass for cashmere! A couple of weeks ago, Duff wore a polo sweater with trousers, pointed-toe flats, and a Chanel tote, creating the chicest rich mom getup.