Thanks for the response. I figured that would be the hazard of modifying the code directly, and which is why I was asking for some guidance :D
I do have the option price stored in the DB already in a separate column. So, if I am currently using this calculation for the price in the cart:
[Price] * [Quantity]
I would want to change it to:
([Price]+$rows_rsPrice['SizePrice']) * [Quantity]
But wouldn't I need to place a recordset somewhere that will use the SizeID that is stored in the cart to grab the price for that size/option? Or is there a way to store it in the cart so it is updated automatically?