Prices during the carnival jump several times. Often Brazilians do not bother, and simply add a zero to the regular prices. But haggling will still be inappropriate. So prepare mentally and financially.
In Brazil, it's very common to buy and book via the Internet. Even a commuter bus ticket is purchased through the website. So do not go without a credit card. Pay by card for the hotel, in large restaurants and supermarkets. But not in small stores and restaurants. It is almost certain that they will try to hack your credit card and withdraw money. In such cases, it is better to withdraw cash from the ATM.
Carnival feeds the citizens and they have absolutely no interest in discouraging visitors with stories of crime. Rio's tourist neighborhoods are no more dangerous than any other city in the world. But don't be a sucker for it - don't leave your things on the beach and don't wear chains or cameras around your neck.
Food and Drinks
Food costs in Rio are not high even during the Carnival. At the cafe-bistro KILO you get all sorts of snacks and pay by weight. Whether it's salmon or just rice. Just to give you an idea of the price level: 100 grams of any meal at KILO costs about $1. 700 grams of food is enough to fill a hungry person's stomach. Very cheap freshly squeezed juices are sold everywhere.
The more established places are also pleasantly cheap. In those same KILOs (we are talking about the more reputable establishments of this chain) there is a special form of cruelty to the customer: the waiter keeps bringing up new dishes and offering to curso de gestao de rh. Until you pay attention to the two-color chips lying on the table. The red side of the chip up means that the client is full, the green side means that he is still able to devour food. But at first no one explains anything to you!
Coffee in Brazil is excellent. As for alcohol, Brazilians use cachaça - cane vodka mixed with all sorts of juices. Beer is excellent. It costs up to $0.75 a bottle. Imported alcohol is expensive.
Be aware that 3* hotels in Rio can often be bad. And hostels are not worth checking into. Poor students who are not in the habit of going to bed at 10pm stay there. That's why it's noisy. And very stuffy, by the way.