To be comprehensive...
Here is a link to programs offered through U of I. Each program is separate and some offer some kind of financial assistance and some don't (GEMS is a fabulous free program but begins in April and I read that the CU Symphony offers scholarships to ISYM).
I can't believe I forgot about College for Kids at Parkland College. They offer a variety of classes in many topics. I think they are a bit hit or miss depending on the instructor (I wasn't too impressed by the cooking class my daughter took last year). They offer some financial assistance to those families who qualify for free/reduced lunch programs but you have to ask.
Bottom line: if you need financial assistance to participate, ASK...you never know.
If you have more ideas about programming or activities in CU, let us know.