The increased cost for the 4 bonds purchased today, based on The Wall Street Journal's quoted values (Bonds=NJ 4.125% 35, Current yield=2.3%, Volume=5, Close=109.875%, Net change=+1.125%), is $790.16.
Let's break down the steps to calculate the increased cost for the 4 bonds purchased today:
Calculate the face value of one bond:

Calculate the cost of one bond purchased today:

Calculate the increased cost for the 4 bonds purchased today:

Therefore, the increased cost for the 4 bonds purchased today is approximately $790.16. Rounded to the nearest cent, the answer is $790.16.