RIO DE JANEIRO >> Once a party of luxury and glamour, Brazil’s most famous Carnival is increasingly being dominated by thrifty tourists more interested in free street parties than the pricy samba school parades.

Cariocas, as Rio de Janeiro residents are known, and tourists used to spend a lot on Carnival parade tickets and costumes. But a grinding economic crisis in Latin America’s largest nation and the rise of “blocos,” as local street parties are known, are changing the nature of the big bash.

Rio’s tourism agency expects a quarter of all visitors to spend less than $100 a day, compared to 12 percent who did so last year.

“We have millions of people willing to take to the streets for the free and cool blocos, while the samba school parades have been frozen in time and become very expensive,” Carnival historian Luiz Antonio Simas said. “For tourists who want to spend less, it is an obvious choice.”

Rio’s tourism agency expects 1.5 million tourists to descend on the city between today and Tuesday, almost 500,000 more than last year. But city revenues during Carnival are expected to be roughly the same as last year, about $1 billion.

Most of the visitors are unlikely to attend parades with the traditional samba schools that have prepared all year for the event. Instead, they will hang out alongside thousands of others at some of the estimated 600 block parties. In 2007, when Brazil’s economy was booming, Rio’s Carnival had only 300 block parties.

Rio authorities and businesses are also shifting their priorities toward the streets and out of the Sambadrome, where the samba schools perform.

While Mayor Marcelo Crivella cut more than $1.5 million in funding for the samba school parades, which represents almost half the budget of some schools, he increased the number of portable street toilets by a few thousand, to 32,560. For the first time, more than 3,000 private security agents will be at work during the party, most protecting street parties.

Much of the appeal of Rio’s street parties is the variety of themes. Any costume, or no costume at all, is fine, and revelers can choose according to their musical taste and location.

The street parties are free, or close to it, and partiers spend what they want on the food and drink being offered.

The experience at the Sambadrome, where top schools parade into the wee hours on two consecutive nights, dates back to 1932. Attendees hear some of the best drummers in the world as they watch massive and gaudily decorated floats roll by, while beautiful people — some wearing very little — sing and dance to samba music.

The Sambadrome parade does try to maintain appeal for thrifty visitors with about 14,000 tickets that cost as little as $3. But those go quickly and are not close to the best sections. The most expensive tickets cost about $2,000.

Parade financial director Heron Schneider says that selling more cheap tickets won’t make the parade more accessible because scalpers would quickly buy them up and resell them for higher prices. He believes low-cost tourists can find good options at the Sambadrome if they really want to go.

“I don’t see a conflict between the parade and the blocos. You can go to both,” Schneider said. “They are different in nature; ours is a show and a competition that has to be paid for. It is not sheer fun.”

Rita Fernandes, head of Rio’s street party association, says the groups that organize them are struggling despite all the people attending. She believes block parties need some public funds and to find sponsors.

“To keep those tourists coming, the street parties need money too,” she said. “Nowadays we get nothing to improve people’s experience.”

The local hotel association expects 85 percent of rooms to be taken for the bash, higher than the last couple of years but still far below the nearly maxed-out occupancy of years past.

Many low-spending tourists in Rio will come from the neighboring state of Sao Paulo, the country’s most populous.

Television producer Rodrigo Rodrigues, 35, is one of those who will stay far from the Sambadrome and expensive hotels. He will travel six hours to Rio by bus, stay at a cousin’s small apartment far from the beaches and cook his own food.

“The street parties are where the pretty women will be,” he said. “Just watching (the schools) parade through the Sambadrome is not the kind of Carnival I want, even if I could afford it.”