This Facebook post from Ziploc has it all: super-high relevance to Mommies (prime buyers), ridiculously high utility, highly visual (and almost instantly comprehensible), and... best of all... you need their product to make it work.
Is it worth a few extra pennies at the store to buy Ziploc instead of the store brand?
It is if you've won the hearts of your buyer!
To get an updated tally on likes & shares, check out the original Facebook post.
H/T: Bob Mullen