Recently, my six year old daughter has taken to reading books in bed before she goes to sleep. I thought a nice gift would be book light. I found what I was looking for at Walmart for $7.99 (model: MAINSTAYS LED Laptop/Book Light; MS32-030-002-18.). The light has a high intensity LED, a flexible stock atop a USB connector, and a battery pack (3xAAAs not included) that provides power to the light through a USB port. The light may be used on a computer through a USB port or clipped to a book using the clip on the battery pack. I bought two, since I also have a four year old daughter (her little sister) who would need her own book light (it’s only fair…to a four year old.)
The clips on the battery packs were the first things to break on both of the kids’ lights. After a couple days of typical six year old and four year old use, both battery pack clips had popped off, and would not hold the battery packs to books. When, my six year old told me she was not able to use her light on her books, I decided I would try and fix it for her.
The clip in question has two nubs that connect to the battery pack through fitted slots molded in the plastic. It appeared that, with the extended wear that children can put on things, the plastic around the slots had worn out. My goal was to find a way to reattach the clips to the battery packs.
I disassembled a battery pack to see what I was working with. When I saw how the clips attach to the battery pack I quickly disregarded my original hypothesis (that this is my children’s’ fault,) and now believe that the clips broke because of bad manufacturing. The nubs appear as though they should have been secured inside the battery pack by a slight bend, however there was no bend, and so the clips popped out. To fix the clip I used a pair of needle-nose pliers to applied a slight bend to the each nub from the inside of the battery pack. 
With the clip secured I re-assembled the battery pack, tested it, and proclaimed it fixed! I then did the same repair to the other book light. Both clips seem to be solid and correct. More evidence in my mind that the manufacture is the cause of this problem. My children are de(lighted) and are once again using the lights to read their books before going to sleep.