This is an offer from Shasta for a free 1 liter or 2 liter soda of your choice. Visit their site and click on the menu button at the top left of the page. The click on the contact link. Once the contact page loads, choose customer inquiry and then coupons. Then you can just need to enter in your mailing address. They will send out your freebie in the mail as soon as possible.
Get your freebie coupons over here.