With Black Friday and Cyber Monday behind us, we're officially in the midst of the holiday shopping season. At some point in the coming month, you might find yourself wheeling a shopping cart teetering on the edge of collapse like a Jenga game. But when you get to the register and the cashier asks if you'd like to open a store credit card for instant savings on your pile of goodies, should you say yes? That depends. Let's take a look at when it makes sense and when it doesn't.

In the land of plastic
Retail store credit cards typically come with low credit limits and high APRs compared to traditional credit cards. The average retailer card APR is roughly 20%-plus compared to the average traditional credit card APR of 15%. That 5% spread can translate into lots of needlessly spent money. So if you typically carry a credit card balance, it's not smart to load up on retailer cards. Promptly tell the cashier, "Thanks, but no thanks".

But if you're diligent about paying your credit cards on time and in full every month, retail cards can help you save a buck. Store card rewards usually come in four flavors: purchase discounts at time of card opening, no interest for a certain number of months, everyday cash back, and ongoing exclusives like special sales or coupons. These cards can really work in your favor if you're a loyal one-stop shopper.

For instance, J.C. Penney (OTC:JCPN.Q) offers its Store Card, which rewards users up to 20% off certain items such as apparel, shoes, handbags, and fashion jewelry. But the merchandise must be purchased the same day as card approval. Meanwhile, Target's (NYSE:TGT) REDcard takes 5% off all purchases every day, offers free shipping on Target.com, and allows an extra 30 days for returns. Just make sure you pay the bills on time and in full by the end of the billing period, since the Store Card and REDcard come with 26.99% and 22.9% APRs, respectively. 

Or if you're in the market for a large purchase and looking to self-gift this holiday season, retailer cards are worth considering. For a long overdue kitchen makeover (that Brady Bunch motif has got to go), home improvement retailers Lowe's (NYSE:LOW) and Home Depot (NYSE:HD) offer cards with enticing incentives. Both feature 0% interest for six months on purchases over $299. The Lowe's card also offers a 5%-off-every-purchase option instead of the 0% interest, which could mean an instant $250 off a $5,000 kitchen overhaul.

For small purchases or retailers where you don't often shop, ask yourself if the savings you'll receive will outweigh the time and energy needed for managing another piece of plastic. Sometimes the hassle just isn't worth it.

Plain-vanilla credit cards
Alternatives to store cards are traditional credit cards with cash-back rewards. Compare the bonuses offered on the store cards to those on traditional credit cards. For example, JPMorgan Chase (NYSE:JPM) offers its Chase Freedom Visa credit card. This traditional card boasts no annual fee, gives you a $100 bonus after you spend $500 in the first three months, 5% cash back for spending on categories that change every three months (hotels and airlines are on deck this quarter), and 1% cash back on all other purchases. And, if you're a cyber shopper, the card gives you an extra 10% cash back when you shop at select online merchants.

Strongly consider whether you want to be beholden to a single retailer's rewards as opposed to receiving cash back rewards from a traditional card where you can spend those dollars anywhere.

Foolish bottom line
If you're a loyal shopper at one particular store, signing up for their credit card may make sense as long as you pay off your balance in full and on time each month. Also, ask yourself if the savings will outweigh the headache of managing another card. And, tempting as it may be, avoid using the discount as an excuse to buy more stuff.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.