Let's see.
I have a swimming pool with 25,000 gallons of salt water.
If I assume I can get 35 MPG from this beast, then that's 875,000 miles.
I average around 4000 miles a year, so I'm looking at 218 years of no cost fuel.
If I got one now for 1.5 Million or so, that's only $6,800 per year, or $1.72 per mile.
Gotta go - putting in my order now, after all I'll be only 288 years old before I run out of fuel.