For better or worse, snacking and gaming seem to be inexorably linked. Now social gaming giant Zynga is building on this relationship, by teaming up with Frito-Lay and Walmart, to offer in-game rewards for its popular Facebook games with purchases of specially-marked snacks.

The promotion is a great way of giving the Zynga brand a strong presence in Walmart stores, where $15 and $25 top-up Game Cards will be sold alongside the snacks. They will be prominently placed, in displays near the check lanes, and will no doubt make a great impulse purchase for some of the 240 million active Zynga game players that will be out doing their weekly shop.

From March 1 to April 12, 2012, the promotional codes will be featured on five million bags of snacks. The codes can be redeemed against exclusive virtual items in the three participating Zynga games — FarmVille, CastleVille, and CityVille.

If you want a Flowery Oak to spruce up your castle, you’ll need to grab yourself some Funyuns. A Spring Dragon can be obtained by eating your way through a bag of Cheetos Crunchy Cheese, and a packet of Doritos Nacho Cheese will reward you with a virtual Nacho Garden for FarmVille. Seriously.

Players wanting to get their hands on super items, such as Glowing Glass Condos or Spring Pegacorns, will need to do some serious snacking. These items are unlocked by redeeming on-pack codes from four different specially marked Frito-Lay snack brands, along with a $15 or $25 Zynga Game Card, in the same game.

Jeff Karp, Zynga’s Chief Marketing and Chief Revenue Officer, said: “This promotion between Zynga, Frito-Lay and Walmart is a fantastic example of how brands can work together to bridge the online and offline worlds, all for the benefit of the consumer. We are continually looking for ways to surprise and delight our more than 240 million monthly active users, and we can’t wait to offer our players online, in-game rewards for their offline purchases.”

Full details of the promotion, including a picture of what a Nacho Garden actually looks like, can be found at the Zynga website.

Just remember, as much as you want that Spring Pegacorn, snack responsibly folks.