Yeah go ahead and buy it and let us know.
The easiest way to get hydrogen is to separate the hydrogen and oxygen particles of water. You do this by connecting a dc voltage to two conductors, usually carbon rods out of a large battery. Space the carbon rods apart, hook up the battery, and shortly you will begin to see bubbles forming on both rods. One is oxygen and the other is hydrogen.
But which one is which? Simply place a burning match directly about the water level next to the rod. The one that burns is hydrogen.
Ok, so that's the easy part, the hard part is containing it for use, the easiest way of do that is to encapsulate the carbon rods in a container with a bottom facing opening, this way you can submerge the container and the rod will still be in the water. Remember, gases rise so eventually the container will fill up with gas and push it to water level if not weighted down.
Basicialy what I'm saying is, you might be able to produce enough hydrogen for actual use if you had a giant tub in the trunk, full of water, with a couple hundred carbon rods but probably not.
Your welcome for your Sunday morning science lesson!