Granted, this here project isn't nearly as inexpensive as the $100 underwater ROV
from years back, but at least this one is propelled by something a bit more advanced than a pull string. Regardless, the ROV
-in-a-Box Project Kit -- created by folks from Carl Hayden High School for use in the National Underwater Robotics Challenge -- is a $249.95 package that "includes all the parts needed to build a working underwater
robot: a frame, motors, underwater light, camera, 50-foot tether, operator control box, and a dry-cell battery." Of course, you'll still be required to provide your own tools and TV monitor, but to take a closer look at exactly what a nickel under $250 will buy you, click on through for a detailed video
(but do tap Mute beforehand, okay?).