According to The Fordham Institute it will cost between
 $3,000,000,000 and $12,000,000,000 to implement CC.

Education Week said it would cost as much as $8,300,000,000 to implement CC.

Some estimates are as high as $30,000,000,000

According to this article in Education News: The total seven year cost for CC would be $15,800,000,000 for the United States.  Of that $15.8 billion, the federal government will pay a total of $5.4 billion (in grants).  That leaves the states to pay $10.4 billion.  The bottom of the article, table one, breaks down how much each of the 45 states involved in CC will have to pay.

I live in Nevada.  The article says CC will cost NV $151,000,000.  The NV State Board of Education approved CC in 2010 with no public input.  On 7/26/13 I emailed all members of the board;
I asked if this figure was accurate, if not what will the actual cost be, and who would be paying?  I also requested they check this article for accuracy.  To date no one on the board has responded to these questions/requests.

Spending an incredible amount of money to: downgrade the math standards, not improve (possibly downgrade) the English language arts standards, create mediocre and controversial science standards simply does not make sense.
4) Incredible cost to implement