How much does a substitute teacher make in Illinois?

I'm sure it varies considerably by state and school district. I'll answer on behalf of many California public school districts. A substitute teacher can expect to earn a flat rate of $100 per day with no benefits. Many districts offer incentives for subbing often (eg. 85% of the month or 15 days a month) or for taking on long-term (11+ day) assignments. So, a "career substitute" should expect to make $125 - $150 per day.

I have known fellow substitute teachers who have had a class for the entire year because of unfilled vacancies. This is not a favorable situation according to Ed Code, but it happens. In cases like these, the district usually must pay the sub according to the teachers' salary schedule.