Adding Values to Specific Cells

Hi,

I want to add a value to each cell then have excel add each value up for me. It is for my business so quantity of products changes on the daily

Ex. Fresh F & F Box is valued at $48 - Skimmed Milk $1,60 etc.... then below will be the quantity each customer wants.

So i want at the end it to give me a total quantity and then the total cost.

HELP PLEASE, ive been trying different things for hours...

Trying to attach my excel file but wont let me.