05/22/2012 01:22 pm ET Updated May 23, 2012

FarmVille Gets Its Own American Express Prepaid Card

American Express is willing to farm for money.

On Tuesday, the financial services company announced the launch of a new FarmVille-branded prepaid card as part of its Zynga Serve Rewards program. Serve is American Express’ digital payments platform.

The card works like any other prepaid card, customers load it with cash and use it like a debit card to make purchases. The difference is FarmVille card holders can earn points to use in the virtual world of the popular Zynga game.

American Express says the card is aimed at people who want to bridge their online and offline spending--and it is hoping that a healthy portion of FarmVille's 22.5 million monthly players want to do exactly that.

You have to play the game to get the card. Farmvillers must plant something called a Serve Money Tree to see a sign-up promotion for the card, linked to a Serve account. You can load the card for free with transfers from your bank account, or for a fee with a credit card or through a GreenDot 'MoneyPak, a money transfer method.

Once the card is in hand, cardholders can earn “Farm Cash” rewards by spending $25 or more in real life on the card. They can use those rewards to spend online and buy tractors, chickens and other agricultural goods to grow their virtual farms. One real-life hitch? Using the prepaid card to get cash from an ATM won’t be cheap--the first withdrawl each month is free, after that it is $2 per ATM withdrawl.

“Together we can add surprise and delight to everyday shopping,” Mark Pincus, CEO and founder of Zynga, said in a statement. American Express said it would be rolling out similar prepaid cards for players of CastleVille and CityVille later this year.

For the New York-based financial service company, this is the latest in a series of new ventures aimed at getting more diverse customers. Last week, it announced the launch of its Campus Edition Prepaid Card, which is marketed at college students and sold both online and through many campus bookstores. The company has also been partnering with other social media platforms, including the geo-tagging app FourSquare, to create deals and promotions for cardholders.

American Express' move to get a younger, online-savvy audience is one way the company is competing for greater market share. While it makes money from prepaid cards' fees (such as the $2 ATM fees), the strategy could help on-ramp customers into other products and spend more, Denee Carrington, a senior analyst with Forrester Research Inc. who previously worked at American Express, told Dow Jones.

It is not the first financial company to eye online games. Both Discover and CapitalOne have offered promotions in FarmVille in the past.