Not sure I follow. You assert that a product will be designed to cost FOO, but then they decide to advertise and they increase the price to FOO + x. That's not how it works, the advertising costs are built in the original FOO, being presentations, conferences, regular ads, you name it.

Companies use advertising to increase their sales, either from 0 to something or from something to something more. Along with R&D, production costs, running costs and profit, the advertising cost is part of the planning from the start.