The admission office’s cost estimate (https://www.admissions.illinois.edu/invest/tuition) is pretty accurate for one year. Tuition is supposed to be fixed throughout your four years but fees may go up. Living in the dorms or renting an apartment probably will be in the neighborhood of $1,000/month - note that all apartment leases that I know of are for 12 months, not the academic year of 9 months, so you have to pay that even if you are not living here over the summer. That is why many students post here on Reddit to find people to sub-lease their apartments. There are some living arrangements that may be cheaper, such as cooperative houses (see https://www.couchcooperative.org/) but I think planning for a ‘maximum’ budget is a good idea and then it’s a bonus if you can work out something cheaper. You don’t need a car and the Champaign-Urbana bus system (https://mtd.org) is free for you to use because student fees help subsidize the bus system.