btw, LLC in IL is 500.00 filing fee.
you have to have someone serve as the registered agent. you can serve as your own registered agent. you do not have to hire someone to be the registered agent. the only benefit of hiring someone is that it will keep your address private. the LLC cannot serve as their own registered agent.
however in IL you must give a business address, and if you're running it out of your home, and have no other business address, then that's the address you must give. PO boxes alone are not allowed on the articles for IL LLC's.