How much will 'cash for clunkers' cost?

The Obama administration's "cash for clunkers" program apparently blew through more than $1 billion in a week. Now, the U.S. Congress is scrambling to pass $2 billion in additional funding. But will that be enough?

Officials from the automotive industry and the Obama administration were clearly caught of guard by the huge popularity of the "clunkers" deal, which gives people incentives to trade in their old, less fuel-efficient vehicles for new, greener models. The problem is that the rules are so convoluted many people and car dealers still don't understand which cars qualify for the program and which don't.