Now that you mention it I have always been big of nabbing freebies
your best bet is for the dog! Once every six months I send an email/fill out the wee contact form on a list of 10-15 cat food/cat treat suppliers. I just say the cats love the food ya da ya da do they have any samples and the stuff I get sent has always been fab. Applaws which does spendy cat and dog food sent me a box with every flavor, did it for my bosses collie and same. A lot of companies just have allocated budget for samples.