NEW YORK (AP) -- Personal finance media personality Suze Orman is thinking big. She's the first out of the gate in the fast-growing prepaid debit card market with a card that aims to help its users build a credit score. It's a gamble that could pay off, if it can help create a way measure the creditworthiness of millions who function outside the traditional financial system.

The latest in a string of celebrities to put their stamp on a prepaid card, Orman will likely avoid the criticism about high fees lobbed at earlier offerings, such as those of hip-hop mogul Russell Simmons and reality show stars the Kardashians. Orman's card costs $3 to obtain, and then just $3 a month, rivaling the hugely popular Walmart MoneyCard.

Although some will question how Orman will recoup the more than $1 million she has invested in the card when charging that little, the real twist isn't the low fee structure. Orman is working with credit reporting agency TransUnion to create a new kind of credit score for users of "The Approved" prepaid MasterCard, one that's based on their spending habits.

Right now, using debit cards - both the prepaid kind and those tied to bank accounts - does not influence an individual's credit score, which is calculated with data related to borrowing. If Orman's experiment is successful, this new type of score could be a game-changer for the estimated 60 million Americans who do most or all of their personal business in cash or with cash alternatives like prepaid cards.

The TV adviser said she approached several companies, urging them to agree to develop such a score, and TransUnion ultimately agreed to gather spending data for 18 to 24 months. It will use that data to try to come up with a formula that works as a way to predict whether the user is a good risk for lenders.

"This is truthfully a work in progress," said Orman.

Banks and other lenders are interested in creating ways to measure how prepaid cards are used, because of the huge market they represent. Consumers loaded an estimated $70.7 billion onto prepaid cards in 2011, up from $2.7 billion in 2005, according to consultancy Mercator Advisory Group.

Mercator projects the market will top $120 billion this year if adoption continues at the same pace.

In general, users can be divided into three groups. The first subset is those caught up in the economy - people who had good credit until it was damaged by events like unemployment or foreclosure. Second are those who have not yet built credit histories, mainly the young and recent immigrants. The third group avoids banks, often because of negative experiences, such as racking up high overdraft fees.

"Wouldn't it be fabulous if, for the first time in history, people are literally rewarded for spending cash, versus penalized, in my opinion, for doing so?" Orman said.

The problem with traditional credit scores from FICO Inc. and its competitors is that they measure how well individuals keep up with their payments, but don't pay any attention to their overall financial health, she said. "Scoring doesn't question where the money is coming from to make payments."

Prepaid cards have already filled some of the void for those who don't use banks, especially because they can be used to receive paychecks via direct deposit. But because they don't contribute to credit scores, the cards can't help users get a mortgage, a car loan or a credit card.

Not having a credit score, or having a low one, also drives up the cost of living in other ways. Lower scores can mean higher car insurance rates, higher rent, difficulty getting a job and paying higher interest rates for any credit available. People with little credit history - known as a "thin file" in the industry - are also the most likely to use alternative services like payday lenders, check cashing stores and bill pay services. These are expensive options when compared with credit cards and banks.

FICO Inc. and other companies use data tied to borrowing to determine a score meant to measure the likelihood an individual will pay back future loans. FICO's 300-to-850 scale is based on an individual's history making payments on loans, the percentage of available credit that is being used and how long the individual has used credit, among other data.

Those with thin credit files have a better chance of having their creditworthiness reflected by FICO's "expansion score," which factors in data like utility bill payments and rent payments. FICO CEO Mark Greene said the expansion scores have shown that the population without traditional scores mirrors to the larger population in terms of credit risk. Other credit score providers are beginning to provide measures based on utility payments and other nontraditional data.

One big difference for developing a prepaid score, however, is that these alternatives still measure how well individuals meet obligations, not how they spend the rest of their income.

"Spending is not actually a great indicator of the thing that we're trying to measure, which is the likelihood you're going to pay your bill," Greene said. "We need to be careful about how we approach that issue."

Another issue a prepaid-linked score must address is the fact that the typical reloadable card is used for just three to four months, said Brian Riley, who analyzes the card market for the consultant The Tower Group.

That timeframe is likely to expand, however, because more users are beginning to have their paychecks deposited to reload prepaid cards. Adding rewards and services, and cutting fees, may also increase customer loyalty.

Orman is adamant that her card will carry only a $3-per-month fee for users who load at least $20 per month onto it. Fees will rise only if the user uses ATMs outside the network it is linked to when withdrawing cash. Consumers who use The Approved Card will also get daily text messages updating their balance, along with one after each purchase, and other free services like ID theft monitoring, credit monitoring and free credit reports from TransUnion.

The media star, whose new show on the Oprah Winfrey Network premieres Monday, said she knows creating the score will be an uphill battle, but believes that if successful, it will help both lenders and borrowers. "You've got to start it somewhere, and this is the beginning of that process."

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