Shoppers also may see more sales tax charges on sites like eBay, Etsy and Amazon if they’re buying from out-of-state merchants that do enough business in Illinois to meet the state’s threshold for collection. Amazon, for instance, has collected sales tax on items it sells directly to Illinois shoppers since 2015. But Illinoisans haven’t had to pay sales tax at checkout when buying from out-of-state merchants who use Amazon to sell their products. As of Monday, that will change, though it will be up to the third-party sellers to determine whether they are obligated to collect.