As the verification process is conducted on items that have already been sold, StockX does not provide value assessment. 

Item value is determined by a Buyer and Seller agreeing on a price and fluctuates from sale-to-sale. You can always determine the current value of any item you're interested in selling on the site by navigating to its product page on StockX. Here, you're able to see current Ask prices as well as data concerning previous sales. StockX provides this information in order to help both Buyers and Sellers make an informed decision that will facilitate a sale.