Free shipping for online purchases used to be the domain of big retailers — Best Buy, Amazon, Walmart and the like. Today, few charge for it, especially during the holidays. In a National Retail Federation survey released in October, 92.5% of online retailers said they plan to offer free shipping during the holiday season. In mid-December last year, 52.7% of online purchases came with free shipping. Some retailers still have certain purchase-price requirements, but the days of free shipping being an exception are long gone.