Do you like light? How about water? Cheap things to make? Well I have a project that is kinda cool if you can do it right. And I did it, so you shouldn't have a problem.
Step 1: Materials
The materials for this is a bit long, but most of them are really easy to acquire.
-Hearing Aid Batteries***
-Water (Not pictured)
*** An easy way to get watch batteries and LEDs are to find really cheap, junky toys at places like Dollar Tree or any dollar store and breaking them open to acquire the goods inside. I bought 36 "flashlight" toys(picture below) for a total of about $24. It yielded 108 watch batteries and 36 LEDs. Buying them separately would be about $13 for a 16 pack of batteries and roughly $2 per LED from Radioshack.