Why didn't they use their powers to get rich?
If I got powers like these kids, one of the first thing I'd do is get hold of some money, at the very least enough to buy a property outright, even if only for no other reason than the power might not be permanent, so I might as well put them to a good use while I can.
Andrew was clearly unhappy in his parents' house, so you'd think this would have occurred to him at least. Okay, maybe he wanted to be close to his mother, but he could have at least attained some cash to get her decent medical care. He waited until she was practically at death's door to do anything about it. Hell, look at that movie, Jumper. A kid with powers uses them to escape his abusive father and have an awesome time. The protagonist in that movie had the right idea, even if he was extremely sloppy. It seemed to me that the three lads in Chronicle weren't thinking about the future.
"Why do you say this to me when you know I will kill you for it?"