Old Navy flip-flops can be had for a song -- a tweet, that is

Now that the summer heat has arrived, it’s time to get some hot new beachwear. And thanks to a promotional campaign just launched by Old Navy, a brand new pair of flip-flops is only one tweet away.

From Tuesday through Thursday, Old Navy will be moving special flip-flop vending machines around in 36 locations in New York and Los Angeles, allowing customers to tweet about the sale on their cellphones in exchange for a pair of shoes. Using the slogan “tweet for your feet,” the sale is the latest installment in Old Navy’s ongoing effort to integrate buyers in its marketing strategies through social media.

“The old model of communication relies on us as manufacturers interrupting customers and forcing our way into their conversations,” said Old Navy Chief Marketing Officer Ivan Wicksteed. “This is more of an opt-in model, and people can choose to engage ... if they want to. I think it’s more inclusive and more fun.”

The vending machines will make their rounds across the greater Los Angeles area, popping up in locations like Paradise Cove in Malibu, the Santa Monica Pier, Venice Beach and Raging Waters.

“No one has pushed this type of retail before. We are taking our flip-flops out to the people and putting them in places where people actually need flip-flops,” added Wicksteed.

Each vending machine is equipped with a screen that will prompt users on what hashtags and phrases to use to tweet. The machine will also ask for your shoe size and dispense one pair per unique Twitter handle.

Old Navy estimates that it will give away about 9,000 pairs of shoes in the span of three days, building up to its annual $1 flip-flop sale in stores on Saturday, June 28. The shoes are normally $5 for two pairs.