I'll be taking a trip (by car) to Chicago for five days at the end of July for 5-7 days for the first time.

What packing tips do you have? I'd like to avoid wrinkles in my clothes and maximize space in my bag. If you have any other travel tips please share!
What should I pack?

Obviously my clothes and other basic needs, but I always seem to forget things..

What to bring in the car? Snack ideas (that won't melt), maps, other ideas?

Ideas to save money and keep my budget in check?
Thanks for your help!