John Adams is among the first in the Presidential $1 Coins series. Congressional auditors say replacing dollar bills with coins could save $4.4 billion over 30 years. (U.S. Mint via Associated Press)

John Adams is among the first in the Presidential $1 Coins series. Congressional auditors say replacing dollar bills with coins could save $4.4 billion over 30 years. (U.S. Mint via Associated Press)