[JWait]

Ok, the best solution there would probably be to make them product variants.
You can set the price individually and it will change when the customer chooses it. The only drawback, if you count it as one, is that the SKU will change for each variant (but you can make them whatever you want as long as they are not duplicated).

You can also eliminate unavailable combinations when there is more than one option per product... for instance, what if the customer orders "green" and "small" and you don't have that available to sell, ever.