[PeppyGPhiB]

Advertising and PR agencies specialize in marketing plans, and those are very different from a business plan. I think the suggestion to go with MBA students is a good one (particularly one with a business plan competition since it's extra incentive to give you a good product); the plan will likely include a little bit of marketing, then once you have your loan and your business together, go talk to a boutique agency about a more detailed marketing plan.