Thank you for the quick reply and suggestion. I am wanting to only offer the free gift to customers that are signed up to my email list, and part of an email campaign. I would not want everyone to be able to "see" a free product in my store as it is really only meant as a deal sweetener for those customers.

Could I make the whole package as one separate package/product and hide it from view and search engines, but still link it's URL to my ad campaign?

You could certainly set up a product that was hidden from the regular store, but featured in your email. However, hiding that product from search engines may prove difficult. Adding a coupon to your email for a certain product might be a simpler solution, though I'm not sure that will suit your needs for this specific promotion.