If I had $US2,000,010, I would sink $US2 million in this Personal Submarine, a spacecraft-looking two-person underwater vessel that can go down to 305m. Then I will use the $US10 to buy a fake Ringo Starr mustache.
The Personal Submarine uses two 3hp vertical/translational thrusters 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 8.25cm thick acrylic and has a diameter of 1.44m, 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]