Glittery tree decorations aren't the only things popping up in some stores and shocking shoppers weeks before Halloween. Some credit card holders already are spotting 0 percent credit card deals to drive up holiday spending.

Some card holders with the Toys 'R' Us MasterCard offered through Synchrony Financial are being offered a 0 percent rate for purchases made outside the toy store chain and its Babies 'R' Us stores. The deal runs through March 31, 2016.

The tagline on the mailing: "Holiday gifts are within reach."

But watch out: After the promotion ends, the annual percentage rate hits 26.99 percent and would apply to any remaining promotional balance.

Miss a monthly payment? You're hit with the higher rate. Consumers must make minimum monthly payments during that 0 percent promotional time period.

Credit card watchers predict that this holiday season will be stocked with plenty of low-rate deals that are designed to encourage consumers to open new credit cards and spend heavily on the cards they already carry in their wallets.

Retailers are optimistic that consumers have a long list of reasons to splurge on gifts for Christmas and the eight-day celebration of Hanukkah, which begins this year at sundown Dec. 6.

The jobs picture looks better. Home values are stronger. Relative bargain prices at the gas pump make more room for extra gifts in monthly budgets. The Deloitte annual retail holiday sales forecast is predicting a 3.5 percent to 4 percent increase in holiday sales in November through January compared with last year's shopping season. That's down slightly from last year's 5.2 percent gain.

Every extra bargain, every extra deal, every extra 0 percent rate can help fuel that spending.

But if you really want to save money this holiday season, keep a watchful eye on the details of these offers:

Odysseas Papadimitriou, CEO of CardHub.com and WalletHub.com, said consumers want to make sure that they understand how the rate could climb after the introductory offer and know exactly when those higher rates will hit a credit card balance.

Many times, some 0 percent promotions are viewed as a deferred payment, and double-digit rates might be charged back to the purchase date if you don't pay the bill in full before the promotion ends, he said.

Consumers need to ask: Is that interest going to accrue on the purchase?

Deferred-interest products can be risky because good intentions don't pay bills in full. In some cases, you'd owe interest going back to when you first made the purchase. So you risk not being able to get 0 percent in November and December.

Some of the promotions for these offers aren't always specific, so it pays to call your card issuer and ask for detailed rules. You've got to pay attention to what cards offer what deals and what spending makes the most sense for you.

You cannot get too caught up in spending more than you should.

After all, if we start holiday shopping before Halloween, we could be pulling out our plastic for tons of toys, glittery decorations and fancy food for nine weeks or more.

Susan Tompor writes for the Detroit Free Press.