If you're an Amazon Prime customer with a furry family member, go make a free Amazon Pet Profile for them! It takes less than a minute and, once completed, you could have a freebie offered on your profile page. Look at the banners under the advertised products to see what you'll get.
My offer was a free $10 off any pet food purchase. I've seen others get a free $5 off any pet supply offer. I tested whether it'd let me get a random dog food item for free – and it will!
However, I plan on buying using my freebie to buy a big bag of food and send it to a local animal shelter!
I imagine these free offers will die fast, so please let me know in the comments if you didn't get anything.