GoPro Dive Mount:

This is sweet because its affordable and gets decent quality footage. It is also very sturdy. The cost comes out to around $50 if you buy everything but most crafts people have a lot of this laying around already.

What to buy:

 At $15 each they're a steal and work great for this project. They aren't bright enough for a primary light but with clear water they do okay. These would work great as a backup light with a retractor like this: Gear Keeper