creating a formula with one constant

[bite_tony]

in my spread sheet below i need the 'closing value' to be the sum of D12(weeks total) times B2(price)
So a week later i need the 'closing value' to be the sum of D19(weeks total) times B2(price)

Basically every week i need the closing value to multiply the weeks total (Column D) with the price (B2)
I Find that when i drag down the duplicate the formula for later weeks it shifts down by seven cells (days) and so B26 multiples by B9 instead of B2.

how do i create a situation whereby it keeps B2 as a constant value?
Thanks for your help

[Bob Phillips]

Just amend it to

=D12*$B$2

[bite_tony]

You make it sound so easy..
Thanks!!