As indicated by the WSJ and others, Amazon announced a number of new devices on Thursday morning. At the bottom end is a new $50, 7-inch Fire tablet. (If for some reason one is not enough, they will sell you a six-pack of tablets for $250.) In the middle is a revised version of their special tablet for kids. Launched last year at $150, the new Fire Kids Edition is down to $100. At the higher end are their Fire HD tablets, now thinner, larger (in the screens), and HD-er. The 8-inch display sells for $150, while the 10+-inch display goes for $230. […]