According to MyFICO, a division of Fair Isaac, a Consumer with a FICO score between 720 and 850 might get a 5.922% rate on a $200,000 30-year fixed mortgage rate. That would give him a payment of $1,189 a month and $228,072 in interest over the life of the loan.

A consumer with a FICO score between 675 and 699 might get a 6.584% on the same loan, which would cost him $1,275 a month, with $259,074 in interest over the life of the loan, or $31,002 more.

The consumer with a FICO score between 620 and 674 might get a 7.734% rate and pay $1,431 per month, costing him $315,021 in interest over the life of the loan. That's $55,947 more than the middle-score borrower and $86,949 more than the borrower with excellent Credit.

Worse yet, a consumer with a score between 560 and 619 might get an 8.531% rate, pay $1,542 per month and pay $355,200 in interest over the life of the loan. The difference in interest paid over the life of the loan between the first and last example is more than $127,000.

See for yourself. Interest rates accurate as of February 26, 2008: