Hello minuz,
I lived in Ottawa from 2006 to 2012 as an international student.
#1. I thought the cost of living in Ottawa to be fairly high given its small size. Algonquin College is not near the city center, so if you want to live near the college rent is not too bad. I never lived out that way, but I remember seeing monthly rent at around $650 per month. Most students can find apartments by looking at ottawa.craigslist.ca or ottawa.kijiji.ca. Public transportation (called OC Transpo) is a bit expensive, but there are routes around Algonquin College to take you wherever you need to go. You will want to talk to someone at Algonquin College about whether they still have access to the OC Transpo Student Pass; that is by far the cheapest option for you. If you are smart, you can find groceries relatively cheaply. There are student discounts for all sorts of cultural events in Ottawa, of which there are many in Ottawa due to it being the capital city.
#2. Jobs can be difficult to find in Ottawa. Many employers want someone who can speak English and French; Quebec is just across the river and many people who work in government (the city's larger employer) are bilingual as well. If you have any other qualifications/degrees/etc. you might be able to find related work, but most students get part-time jobs in the retail or service industries.
#3. If I can generalize, there are three kinds of people in Ottawa: people who work in government, students, and everyone else who just happens to live there. I spent more time with students and government people I knew secondhand. I found the students to be extremely friendly and most colleges and universities in Canada have many programs designed to get international students out to meet people and explore. However, there are definitely cultural differences that you will have to get used to. You will have to take the initiative when it comes to being friendly with other people, especially Canadians. Everyone is different of course, but if you are honest and outgoing I'm sure you will have no problem making friends.
Feel free to ask if you have any other questions. I lived in Ottawa as an international student for a while so I'm pretty familiar with the place.