ATLANTIC CITY — While Three Dog Night was onstage at the Trump Taj Mahal Casino Resort, singing about how one is the loneliest number, Fred Shields was thinking that 10 had plenty of company: that's how much his and everyone else's ticket to the concert cost.

And then when it was over, Shields and thousands of other fans hit the slot machines, table games, restaurants and bars, providing a bump of $100,000 in revenue the casino otherwise wouldn't have gotten.

The concert was a prime example of a little-noticed trend in Atlantic City, the nation's second-largest gambling market, which is struggling to hold off fierce competition from casinos in other states in an uncertain economy.

And while many casinos concentrate on adding luxurious amenities like spas, pools, and 5-star restaurants to go after high-end guests, many are also competing just as fiercely at the other end of the spectrum, going after low-rollers with low-cost promotions aimed at getting enough of them — and their limited disposable cash — into the casinos.

The Three Dog Night/Creedence Clearwater Revisited show was a natural to attract Shields, a 64-year-old from Oaklyn, N.J. who used to listen to those bands as a serviceman in the Vietnam War. The last time he can recall a $9.99 concert ticket was in the 1970s, when he saw Three Dog Night at the Philadelphia Spectrum.

"That's pretty cheap," he said of the recent show's price. "We jumped on that."

After the show, he and his wife, who were dancing in the aisles like teenagers, planned to eat dinner at the recently opened White House Sub Shop inside the Taj Mahal, where they planned to spend about $60.

Dave Kreiss, a 55-year-old from Philadelphia, said the last time he saw $10 concert tickets was when he was 15.

"Loggins and Messina, maybe?" he said, referring to the popular '70s pop duo. "We wouldn't have come here tonight if it weren't for this."

And when the last note of Creedence's last song was through, Kreiss was headed for the gambling tables, where he planned to bet "a couple hundred dollars."

Bob Griffin, CEO of Trump Entertainment Resorts, was delighted with the response to the cut-rate concert.

"A lot of those people went into the bars and restaurants before and after the show, and onto the casino floor after it was done," he said. "We saw a big surge before and after the show. The high-price restaurants did their normal Saturday volume, but the lower-priced restaurants — the coffee shop, the burger joint and the sub shop — were absolutely slammed with business."

The show cost just under $80,000 to produce, including paying both bands. But Griffin said it generated an additional $100,000 in profits that night when gambling, food and beverage revenues were counted.

About half the 5,300 tickets were bought by cash customers; most of the rest were given free as comps to gamblers who had to play surprisingly little to qualify.

"If you're a $75 average player — if you gamble $75 per visit — on Saturday night you would have gotten a free show, a free room and a free buffet," Griffin said. "In this economy, people want value. We have to remember that Atlantic City has competition it didn't have five years ago. If you can offer value on a summer weekend night, you'll pack your house."

The casinos need it — however they can get it. The resort is in the midst of a 4 ½ year revenue slump started when the first of Pennsylvania's 10 casinos opened, taking away a good portion of Atlantic City's business.

Since 2006, Atlantic City has lost a billion and a half dollars — nearly a third of its business — and thousands of casino jobs as casual customers opt to play closer to home instead of making a three-hour round trip to the Jersey shore. Its gambling revenue fell from $5.2 billion in 2006 to $3.6 billion in 2010.

Resorts Casino Hotel has been offering customers a full steak dinner for $2.99 after 11 p.m. on weekends, and has been among the most generous with promotional cash for new customers who sign up for a player's club card. Resorts will reimburse the first $100 of gambling losses for new club card members on their first visit.

It also offers its seafood buffet with costly king crab legs for $19.20 to emphasize the casino's 1920s theme.

Fresh off being torched for two payouts of more than $5 million to lucky gamblers in recent months, the Tropicana Casino and Resort is taking lemons and making lemonade out of them. It's conducting its own version of the state lottery, giving patrons a free daily ticket for five random drawings each day in which 60 numbered balls will be selected by a lotto-type air blowing machine. Matching 3 out of 6 numbers wins $25 in free slot credits; matching all six wins $5 million.

You're definitely looking for ways to attract new business that don't break the bank," said Tony Rodio, the Tropicana's president and CEO.

And new customers who sign up for a player's club card and them gamble for 30 minutes or more get a free hotel room, free parking and up to $250 in free slot play on their next visit. The Trump casinos offer free slot play of $25 to $250 for new signups.

The four casinos owned by Caesars Entertainment — the Showboat Casino Hotel, Harrah's Resort Atlantic City, Caesars Atlantic City and Bally's Atlantic City, offer a variety of cash and other comps to new customers who sign up for a player's card. They include $10 worth of free slot play, free parking, vouchers for free drinks, a free admission to The Pool on Wednesday nights, buy-one-get-one-free buffet and dessert deals, $10 off a cooking class and other incentives.

The Showboat is holding a free concert by the Gin Blossoms July 23.

And The Golden Nugget, formerly Trump Marina, gives all new club card members $5, $100 or $1,000 in free slot play, based on the spin of a wheel.