If I had $2,000,010, I would sink $2M in this Personal Submarine, a spacecraft-looking two-person underwater vessel that can go down to 1,000 feet. Then I will use the $10 to buy a fake Ringo Starr mustache.
The Personal Submarine uses two 3-horsepower vertical/translational thruster powered by electric batteries and controlled by a central joystick that, according to the manufacturer, allows "precise positioning underwater". The transparent sphere is made of 3 1/4-inch (8.25 centimeters) thick acrylic and has a diameter of 56 3/4 inches (1.44 meters), enough for two people.
Fully certified by the American Bureau of Shipping as a +A1 passenger-carrying manned sub, it comes four external 150-watts quart-halogen lamps to illuminate the way, plenty of power to take video and photographs. It also has a VHF radio to talk with the surface, a GPS receiver, and all the instrumentation needed to navigate your way under the sea, in an octopus' garden in the shade. [Hammacher Schlemmer via Uncrate]