Custom Field that Grows according to quantity

[woogygun]

I have a business card store i am building. The cards have certain addons such as lamination, vynl coatings etc. Each configuration affects the price. lets say the minimum order will be 100 cards at $100, and lets say lamination costs $0.5 per card i need the custom field to add that for each of the 100 selected. So basically the quantity (100) x the addon (0.5) + the Quantity = the price

100x0.5=50 +100= 150

can this be done?