It seems like every retailer is offering its customers its own credit card nowadays. While the incentives to applying for a new store credit card are often enticing — many stores offer 25% off the first purchase, no interest for one year, or monthly discounts or gifts to cardholders — having so many store credit cards in your wallet can put you into debt in a hurry, if not seriously hurt your credit score.

High debt is often a problem for holders of store credit cards, since they generally charge much higher interest rates than bank-issued cards. Unless you plan to pay off the full amount of the balance each month, expect high finance charges, likely enough to render obsolete any cardholder incentives you may have received.

Having a different card for each store you shop in may earn you some store rewards here and there, but holding so many cards does not look good to creditors and thus, your credit score is likely to take a beating. Consumers should balance their card portfolios carefully and only apply for cards with genuine value, according to the National Retail Federation's senior VP Mallory Duncan.

The reason why stores are able to offer such huge incentives to their cardholders is because they reap huge savings on the transaction fees that Visa, MasterCard, Discover, and American Express charge. Visa and MasterCard charge a fee of 2% for each transaction, which comes directly out of the retailers' bottom lines. When a retailer co-brands with Visa or MasterCard, often times that fee is halved. When they offer their own independent card, the retailers can avoid the transaction fees altogether. While some of these savings are passed on to their customers, consumers should still exercise sound judgment when offered a new store credit card. More is not always better.