on the left hand menu click on Self-fulfilled Products
The in the menu that appears in the middle select Products List
You want to create a new product.
Fill out the next form that comes up. Under the price you will only put what your cost is, not what you are actually charging.
Then go to Price Lists
If you want to see the full view of all your products, click Full on the right menu
So now you need to add the product you created earlier.
Your products are set to go to Other Products
Find what you want to add. Then you can set the price and see the profit.