Index Cards
You probably know how often kids go through one pack of index cards while they study for their exams. At the dollar store, one hundred cards only cost 50 cents! In addition, you can stock up on a dozen packs for $6 if you like to buy in bulk.
Flashlight
This item may not have the best quality, but the mini flashlights can be very handy at times when the power goes out. They also have a keychain hook. They are super cheap, so why not?