Burger battles are heating up, with chains heightening competition on both the low and high ends of their menus.

Jack in the Box Inc. (JACK), a burger chain with more than 2,200 U.S. stores, said Monday it would sell its Big Cheeseburger, which features a "jumbo" beef patty with cheese, mayonnaise and ketchup on an oversized bun, for $1 in a limited-time offer.

Wendy's, the third-largest U.S. burger chain, also this weekend launched a promotion tied to its 40th anniversary, selling four items for 99 cents each, including its version of a double cheeseburger called the Double Stack. Wendy's is owned by Wendy's/Arby's Group Inc. (WEN).

At the high end, CKE Restaurants Inc. (CKR) said Monday it was launching "round two" in its own premium burger battle with McDonald’s Corp. (MCD), with Hardee's selling a Big Hardee, with three beef patties and two slices of cheese on a seeded bun, as its version of the Big Mac.

CKE, which owns Hardee's and Carl's Jr., accused McDonald's of copying its premium burgers in developing its $4 Angus burger. In turn, CKE has taken liberty in mimicking the Big Mac, and offering it at cheaper prices. The Big Hardee is for sale for $2.29 a participating restaurant, which it says is 70 cents less than the average price of the signature burger at McDonald's.

The moves are all putting cheaper food in front of their customers, as fast-food chains look to rebound from a summer of disappointing sales where high unemployment among teenagers failed to give the chains a once-reliable summer lift. Breakfast sales are also taking a blow with fewer workers stopping in during their commutes.

Rampant discounting has been a concern for investors in the space, as lower prices put pressure on sales.

Fast-food chains may also be trying to hold onto customers who may be feeling better about spending more for a meal out. RBC Capital noted in a recent research report that consumers seem to be trading up more to casual dining restaurants.

With costs for ingredients like beef lower, many chains have been emboldened to cut prices to lure customers.

McDonald's, after last week reporting same-store sales rising 2.2% worldwide and 1.7% in the U.S., said it would give out 75,000 coupons for free Angus burgers in select cities.

Burger King Holdings Inc. (BKC) has also recently been mailing out coupons that include a $1 double cheeseburger and is planning an ad campaign focused on $1 items next month.

Jack in the Box, Wendy's/Arby's and CKE shares were trading higher Monday, with McDonald's down slightly and Burger King flat.

-By Paul Ziobro, Dow Jones Newswires; 212-416-2194; paul.ziobro@dowjones.com