Moving formula accross cells

im doing a spreadsheet trying to work out price per square foot values against different size appartments in different areas of london to compare and contrast prices.

i set up the formula for one value per square foot, in a cell, and then used this to multiply by various values of different sized appartments.
I am now having difficulty multiplying this accross different columns correctly..

below is the formula i am using which i hope is correct.

=SUM($H$2*$D$4)

i want to then use new values in subsequent columns ie ; j2 but still be able to multiply this back to d4.

and then spread this across the spreadsheet for other values to be multiplied by cells in column d - (4-12 say..)