re Kitty Litter in buckets or bags - I just got Amazon Prime for free with five $30 Metro-by-TMobile lines. Amazon notes that Prime's free delivery includes big heavy bags of pet food and presumably kitty litter. I expect many people will take advantage of this free delivery.
Amazon and Harbor Freight's new methods illustrate the most important thing I learned in business school: 'Expect constant change so surf the inevitable wave of change instead of being dunked by it'. These two recent businesses illustrate this as they replace, for example, Sears and Craftsman.