There's been a few attempts at the amphibious car over the past few decades, some of which worked better than others. This one seems pretty good though, and it promises to be cheap. It's called the WaterCar Gator.
WaterCar, an American manufacturer, says this completely amphibious Jeep Wrangler lookalike can be had for just $US29,500 (around $30,000). For that you get a special gearbox, a fibre glass body and a waterjet motor setup. The company also provides high-torque axles, special suspension and plenty of stainless steel fixtures and fittings.
One part of the car that doesn't come with the purchase is the engine and a chassis. But it's okay though, WaterCar says all you need is the engine and chassis from a Volkswagen Beetle, which shouldn't cost too much.
It looks pretty fun and easy to use, and at that price, great value for money; a car and a boat for the price of a car.
Check out the video below for some demonstrations.