Think of it this way:
A clunker that travels 12,000 miles a year at 15 mpg uses 800 gallons of gas a year. A vehicle that travels 12,000 miles a year at 25 mpg uses 480 gallons a year. So, the average Cash for Clunkers transaction will reduce US gasoline consumption by 320 gallons per year.
They claim 700,000 vehicles were purchased through the program so that's 224 million gallons saved per year. That equates to a bit over 5 million barrels of oil.
Five million barrels of oil at $70 per barrel costs about $350 million dollars.
So, the government paid $3 billion of our tax dollars (through Cash for Clunkers) to save $350 million.
We spent $8.57 for every dollar saved.
I'm pretty sure that the government will do a great job with health care though.