Prime members only. Amazon has a Purina Cat Food Sample Box bundled with a $6.99 credit that can be used towards the purchase of select Purina items (shipped and sold from Amazon.com) for $6.99 with free shipping. Includes 6 or more samples.  Usually ships within 1 to 2 weeks.

The promotional credit will be added to your Amazon account a week after the sample box ships; you'll also get an email with instructions on how to redeem it at that time.