Budgeting

Is there a good source for a generalized advertising costs in every channel?

Background: I am a DECA student creating an advertising campaign for competition and I need to create a budget for this campaign. While most students select brands they made up, or local brands, I decided on a failed corporate brand: Circuit City.

Unfortunately the information specific costs of advertising on the scale of a company like Circuit City are difficult to find.

At the international level real advertisers will be judging, so I cannot throw numbers around, and the cost analysis itself is 2 pages worth. I have some general costs down, but there seems to be some chart or graph or entire website on the internet I am missing, because the costs I have are coming from blogs and forums, nothing professional.