If your advertising goal is to elicit a response, you have two choices for buying media. The first is traditional direct response, which involves placing spots on stations at reduced rates without expectations of clearing every spot ordered. There will be a unique phone number or URL on the spot to track the results. The money spent could yield a great response, or none at all. If your secondary goal is brand awareness, the lack of response may not matter as much, as there is still value in reaching a mass audience.