Clunker for $4,500 dealU.S. President Barack Obama has signed into law a $2 billion extension to the popular "cash for clunkers" auto rebate program.

Mr. Obama signed the legislation Friday. The Senate approved the extension late Thursday.

The "cash for clunkers" incentive program has helped boost U.S. auto sales. The program gives car owners up to $4,500 in rebates to trade in older, gas-guzzling vehicles for newer, more fuel-efficient models.

The House of Representatives approved the bill last week to replenish funding for the program, which nearly exhausted its initial $1 billion funding limit within a matter of days.

The Obama administration had said the program would have gone broke by Friday if Congress did not approve the extension.  

Some information for this report was provided by AP.