This example is focused in those kind of products for bulk selling, for example, vinyls, curtains, bricks, tiling, seeds, etc.
You can configure a base price for that products, and then, depending of the options chosen by the customer you can modify Final Weight of the product, just before adding to the cart.
This kind of products should use a weight based shipping so activate it in Extensions > Shipping > Weight Based Shipping.
There you can set up different ranges of weights and prices, that will be used by OC to calculate final costs, given the final weight calculated by CFO.
Read more about Price, Quantity, Value, Weight, Points…