Market a Free Trial Offer

I work with a company that offers a free 14 day trial of a new teeth whitening product. The person just pays a shipping charge of 6.95 to receive the product. After 14 days of ordering they can cancel the trial online- they do not have to call anybody in order to cancel. With the popularity of teeth whitening products and the fact that this is a free trial it seems that it should be easy to market. I have banners and text links for you to view in order to generate a marketing plan. Before I soend a great deal of money on marketing I'll need to see that your methods are effective through a small scale project.