I am trying to use a formula or function that will look at a cells say column
A check for a condition, if true, then add the value of another cell that is
on the same row to another cell. Yes I know that may be difficult to
understand so let me give you an example.

A B C D
1
2 dvd 25.23
3 cd 12.25
4 dvd 25.23
5 cd 12.25
6 bat 19.25

ok so what i want to do is look at column A, and look for any cells that
have dvd and add the corresponding value from column D to cell B1. So in
this case we can see the cell A2 and cell A4 is dvd so I want to add cells D2
and D4 and that value being placed in B1. Also, how could do the same thing
but look for multible conditions from column A, if i wanted to add the total
value of anything that has "dvd" and "cd" in Column A