Well, you wouldn't necessarily send that letter in the market to all your customers. You can elect to send it simply to your segment created for fans from the Transformers. The better targeted your correspondence is the better. Your subsequent newsletters to that particular segment could even be tailored for upsell other considerations associated with the Transformers...
Each time you sell a specific thing Aweber will automatically email your customer giving them the choice to subscribe to your newsletter. As soon as your customer does they essentially grant you the permission to contact them.