How to modify an attribute in your cart.
After you have added your desired options to your attribute, you can modify that attribute to have specific product qualities.
The below image shows that each item has specific qualities. The number in the first field is the cost modifier, and the number in the second field is the weight modifier.
In order to specifically modify a small blue item to be cheaper or more expensive than other items you would have to combine size and color into one modification and list each available item as shown below.
The Large Blue item in the above image is one dollar cheaper than the other items.
