Fast-food ordering hacks can save money

New combo offers are boosting sales at fast-food and quick-service restaurants.

You've probably noticed McDonald's "McPick 2" deals and Burger King's "5 for $4 deals." According to the NDP Group, which tracks checkout receipts, those combo deals helped sell 100 million extra meals so far this year, increasing 20 percent from 2015.

"The key thing in why these combo meals have been so successful is, I think there's still very much a large percentage of the American population that is really driven to value," said Morningstar's R.J. Hottovy.

NDP research shows that fast-food promotions are so popular that Americans take advantage of them one in every three visits. But you could even more cash by ordering off the menu at McDonald's.

RatherBeShopping.com; says that if you like Chicken McNuggets, order multiple four-packs instead of the 10-count nuggets. The 4-pack is cheaper, and you can save about $1.30.

And did you know that you can order any McDonald's burger with special sauce, lettuce, pickles and onions on a sesame seed bun? Ask for a Mc-Double "like a Mac," and it will cost you about $2 compared to $4.19 for the real Big Mac.

Another hack: The blogger claims that you can ask for discounted food at McDonald’s. Food that has “gone begging” may be burgers and fries that employees made that might have been sitting under the heat lamp a little too long. The store is willing to sell them more cheaply, like 75 cents for a Big Mac.