Amazon has got this 4-pack of StarKist Chunk Light Tuna 5 oz. cans for $2.98 (75 cents per can). Limit 10 per account.
This is an Amazon Add-On item, which means that it ships for free with a $25 minimum order if you are an Amazon Prime member (and its price of $2.98 counts towards that $25), or it ships for free with a $49 minimum order if you're not a Prime member. You can buy multiples of any of this item to help get you to your $25 or $49 minimum for free shipping. (Other Amazon Add-On item deals can be found here.)