Using SUM with Data Validation.

Hello, I am ok with excel but I cannot figure this out. I am trying to make a list of different items and their cost as I go through the list I want to have a data validation (Drop Downs) determine if the cost should be summed or not so for example in column D row 3 starts the data validation (yes and no, the data is linked to Column S row 1 and 2 respectively). In column E I will put the price of the item. In F3 I want the total of the Yes validated items to appear. For example:
_D_____E______F___
Sold | Value | Total
_________________
Yes | $5.00 | $6.25
No | $22.00 |
Yes | $1.25 |
No | $6.00 |
No | $4.00 |


Is this even possible. Basically ignore the value to the right if the validated data is No. Do I need to change something to make this happen? Thanks in advance.