The better suburbs are expensive. The lousy ones are cheap. In general, Chicago's cost of living is less than in California, or NYC - but much higher than most other cities.
Chicago has more than 200 suburbs. It is impossible to tell you where to live. There are a lot of web sites that can provide you with housing, school, employment, social, racial, transportation, culture, and other statistics. It is easy enough to do a web search to find them.