Remember when you were a kid, and you just HAD to have the latest McDonald’s Happy Meal toy? Whether it was a Beanie Baby or a Hot Wheels car, you probably devoured many chicken nuggets and french fries to collect all the toys you could. Your little kid brain probably didn’t realize it, but you were witnessing one of the most underrated tools in a marketing professional’s arsenal: co-marketing.  Even though your Happy Meal days…