I once travelled from Recife to Foz do Iguacu, a distance of 2500 miles which took 3 days and cost Cnd $180.(Not bad I here you say) Not only is this cheap but it also gives you the opportunity to see Brazil changing from the tropical regions of the North to the cooler climatic regions of the South.

Three types of long distance Bus

Ordinary Bus (comum) These buses are the cheapest they normally have a toilet but no air conditioning however the windows open.

Executivo These buses include a toilet and air conditioning.

Leitos These are the most expensive, they are spacious and very comfortable. They have large fully reclining seats provided with pillows and blankets. On board there is a toilet, movies (normally the latest video releases in English with Portugeuse subtitles) and as much coffee, mineral water and soft drinks you can throw down your neck. Even though this is the most expensive bus option it is quite an economical descision as most leitos leave at night. Hence, saving on the cost of a hotel room.

All of these types of buses stop every 3 to 4 hours at a Bus Terminal (Rodoviaria) for up to 30 minutes. Most Rodoviarias have a restaurant, newspaper shops, toilets including shower facilities, post office, telephones and ATM machines. (so make the most of the stop as it will be a long time before the next one.)

Buying Tickets

The usual place to buy bus tickets is at the Rodoviaria. There are lots of different bus companies such as Sulamericana, Penha, Itapemirim and Pluma. Note, that more than one bus company will travel to your desired destination hence hunt for the best price.
Try to buy your tickets as early as possible or at least a few hours before. This is advantageous as it normally guarantees you a seat and a choice of options such as a smoking/non smoking,aisle or window seat.

Alternatively, if you don't want to make the journey to the Rodoviaria which are normally located on the outskirts of a city. You can buy your bus ticket at most Travel Agents. They normally sell long distance bus tickets for the same price as you would find at the Rodoviaria. They do tend to be more helpful as most know some English.

Tips

If you do consider travelling long distances by bus, purchase a pillow or something to support your head so that you can sleep.

If you are travelling on a bus with air conditioning, which you may think a luxury during the heat of the day. Be aware at night it gets very cold in the bus, and I mean cold. So take a blanket, I woke up once to find my face sticking to an icy window.

When the bus stops at a Rodoviaria for a break make sure you get back on time or keep a watchful eye on the bus as it may just go without you.