You can also buy an I-pass for $10 at the first Illinois rest area you come to. They will also make you put 30 or $40 on it in addition to the $10 purchase price. This assumes that there are no toll roads before you get to Illinois and you arrive during normal business hours when the I-pass office is open. The I-pass works on the EZ pass system but for some reason Illinois did not adopt that name. I have used my I-pass house all the way out to the East Coast without any issues.