Budget blog Wise Bread discusses financial products and deals that almost everyone should avoid, and at least one of them has been offered to likely every single reader of this blog—store-branded credit cards, often with a same-day savings pitch. But even if you pay off that purchase the minute you arrive home, it's generally a bad idea:
Do not be enticed to sign up for these cards even if the store gives you 30% off on the day you sign up ... These are different from a cobranded credit card that can be used anywhere. An example of a co-branded credit card is the Costco Amex Card, which can be used outside of Costco. Co-branded cards generally have better rates and better internal controls than store specific cards.
As noted by BankRate.com, each store card opened automatically knocks 20 points off your credit score, making a discount on one sweater not as appealing. Hit the link for five more items to keep your distance from.