What’s the worst part about shopping? Well, besides not finding what you want on the shelf or having to pay more than you want to, many people would answer that long lines at the checkout are the bane of any retail experience. Walmart is trying to carve into those wait times with a new iPhone app it’s testing that would allow customers to scan their items in the aisles as they shop, and then simply pay at a self-checkout counter when they’re done. [More]