Money: I definitely spent much more than what was given in the stipend. You are given about R$20 a school day to spend on transportation and lunch. Lunch is generally weighed by the kilo so the more you get the more you spend, I think I got around R$14-15 every day (it's kind of expensive depending on where you go) and then it's R$5 to and from school using the bus. However, the stipend does not cover all of the things you do on the weekends, weeknights, taxis etc. so I would be prepared to bring as much extra spending money as possible. Taxis are about the same cost as they are in the United States but otherwise everything else is pretty cheap comparatively. I did not keep track of my spending that well but I know I came in probably with at least R$1000 just in case.
Free time: Therewas not that much free time on SIT. That being said, knowing that in the beginning is important so that you utilize every spare moment you have in Salvador. We used to go to the beach after class every day and go out multiple times a week so that we could get to know the city and the locals. The way the program is set up, there is lots of traveling. As soon as you get settled, you will start to travel around. Bahia- which is great and was my favorite part, but be prepared to be uprooted. You will have a Spring break in which some people travel to Rio or the Amazon or wherever. My friends and I went to Itacare and Morro de Sao Paulo which you will hear a lot about because they were beautiful and I highly recommend going. If you want to travel extensively around Brazil I would highly recommend staying after the program ends to do so- that way you can make friends on the program and travel together after and you will have enough time to truly enjoy it.
Portuguese- I knew Portuguese coming to Brazil so I was definitely in a lucky minority. Most people in the program do not know any. I would recommend doing Rosetta Stone or looking through a language book now to start familiarizing yourself. Most Brazilians do not speak English so you will feel a lot more comfortable knowing a little Portuguese, and it will also put you in a higher level Portuguese class so you will learn more. This was probably the biggest complaint from my group, because there was a lot of miscommunication and people feeling totally lost. You will be fine as long as you are prepared for this feeling.
You will probably feel a little lonely and uncomfortable in your homestay the first couple of days. I promise you though, that uncomfortable feeling will go away. The SIT families have been doing this for years and they know how to host students and will not speak any English with you so that you learn faster- they are doing you a favor. Also it is really fun and they are so friendly and silly you will love them, so many people cried on the last day leaving them. They are a great resource- use them! Also we had no trouble meeting locals pretty immediately. Just being outgoing and going out to Pelourinho and Rio Vermelho will bring you closer to Brazilian locals. They are incredibly talkative and outgoing and love meeting Americans so it shouldn't be too hard with a little effort. Distance to homestay location really shouldn't be a problem. There were some people who lived further than others, but everyone is grouped near each other. When you are going home at night you are generally advised to cab anyways since public transportation is dangerous no matter where you live, so I wouldn't worry too much about this. One of the best semesters of my life, you get very close to your group and you will be sad to leave!