Wal-Mart-Stores (WMT) will stop selling Amazon.com's (AMZN) Kindle e-readers and tablets once inventories run out, mirroring rival Target 's (TGT) move last month. The world's largest retailer didn't say why other than it was a business decision, according to Reuters, which first reported the move. Amazon didn't comment. Wal-Mart still carries other devices including Apple 's (AAPL) iPad tablet and Barnes & Noble 's (BKS) Nook e-reader. It also