Reddit mentions of microtivity IL151 5mm Clear White LED w/Resistors (Pack of 30)

• Fire TV Stick, which is a lower-cost alternative to the awesome Fire TV. (think Apple TV, but actually good)
  
  
• Raspberry Pi which is a tiny fully-functional/fully-featured ARM computer.
  
  
• Arduino, which is an easy-to-use electronics prototyping platform, great if you're interested in learning how to make your own electronics and whatnot. (you might also want this, this, this, this, and this. Should be less than $40 altogether, though you could also probably find like a starter kit that comes with an arduino, book, and components.)
  
  
• Huion drawing tablet, great for if you want to do digital art. I haven't used this model specifically, but I do have the (bigger/more expensive) Huion 610 Pro, which I love.
  
  
• Amazon Prime student was like $40 IIRC, not sure if that has changed though.

I would use LEDs and a small 9 volt battery to keep size/weight down. you could add more 9 volts to increase capacity.

http://www.amazon.com/microtivity-Clear-White-Resistors-Pack/dp/B004UZCMRK/ref=sr_1_11?ie=UTF8&qid=1314079567&sr=8-11

To get the 9 volt voltage drop with these LEDs, you would need 3 parallel wired sets that were in series of each other.