Hi, Ben.
I live a little bit far from Copacabana (kind of 30km), but there is a nice place to stay. Things in Copacabana are more expensive, because it is a typically touristic neighbourhood.
Carnaval is the most expensive period of the year, but you can have lots of fun and the best carnaval you have ever had without spending so much money!
I've never been at Via Show, but people say it is a very good place to go, despite of being an environment known also to be more dangerous, and according to what I heard, more frivolous also. But I don't know,I'm just speculating about that.
If you want to choose between Spanish or Portuguese, I suggest you to learn Spanish, cause there are more countries that speaks that language.
Brasilian people understand something about spanish only because a lot of things are similar, but most of brasilian population dont even know a lot of portuguese... Hehehehe... It is more difficult for spanish speakers to understand brasilian ones, because we have a lot of words that we put together (like "wanna" for you in US), and because a lot of brasilian people talk fast and dont speak correctly the portuguese.
For more information, a little bit about other places to visit in this wonderful country:
You have much much more fantastic places to know here.
For example, Pantanal Matogrossense, a tropical wetland and the world's largest wetland of any kind. It lies mostly within the brasilian states of Mato Grosso and Mato Grosso do Sul and it also extends into portions of Bolivia and Paraguay as well.
The Lençóis Maranhenses National Park (Parque Nacional dos Lençóis Maranhenses) is located in Maranhão state, in northeastern Brazil, and it is an area of low, flat, occasionally flooded land, overlaid with large, discrete sand dunes. It encompasses roughly 1000 square kilometers, and despite abundant rain, supports almost no vegetation.
There's also Chapada dos Guimarães, a kind of county and mountain range located in central Brasil, at Mato Grosso state. It is surrounded by savannas (we call cerrado) and the Amazon rainforest. Many people travel to see the wildlife, waterfalls and canyons in the area.
Rio Grande do Sul state has a great potential for palaeontological tourism, with many palaeontological sites and museums in the geopark of paleorrota. Ecotourism is very popular in the cities of Gramado and Canela (wich have the best chocolate in Brasil); their cold weather is among their attractions for internal tourism. Tourism is also high in the wine regions of the state, principally Caxias do Sul and Bento Gonçalves. The pampas of the native Brazilian gaúcho are both a national and international curiosity to tourists and their customs are alive in the capital city of Porto Alegre as well as in the cities of the "interior" or western Rio Grande do Sul such as Santa Maria and Passo Fundo.
In the city of Nova Prata, in way the native bush, there is a park thematic, with sources that gush out thermal waters in a temperature of 41°C, which possess excellent medicinal properties and therapeutical.
The state of Rio Grande do Sul and its cities have developed a series scenic routes to appeal to tourists. The Rota Romântica is a popular scenic drive that exhibits the diverse Germanic culture of the mountainous regions of the state referred to as the Serra Gaúcha. One can visit the state's Italian settlements through Caminhos da Colônia, tour the wine country through the Rota da Uva e do Vinho and visit a subsection of the Rota Romântica called the Região das Hortênsias, the region filled with beautiful blue hydrangea flowers each spring. In the far western area of the state are the remnants of Brazil's 17th century Jesuit missions or reductions (aldeias) to the Guaraní Indians.