 And you better fill up your gas tank this weekend. The annual right of summer in Illinois is approaching soon with another hike to the state's gas tax, along with a slew of other taxes beginning Monday. In total, Illinois will see $1.1 billion in tax hikes over the next year. They will support a record-high $53 billion state budget. Taxes for gasoline will be $0.47 per gallon and $0.54 per gallon,