That is very true for some degrees, but I laugh when potential C-S students say this.
My first year of undergrad at well performing state university, I took loans and worked at the schools IT support center, 7.50/hr. The following summer I worked as a "Application Development Intern" and made $10/hr. For the following three years I worked part-time at a local software consulting firm and made $15/hr and part-time as a C-S TA and made 10/hr. I paid off my debt 2 months after graduation and I got lots of great experience.
My story is very typical of my C-S and IS major classmates. And now those same internships in my Alma mater's town are paying 17-18/hr.
So when people say that can't afford to get a C-S degree I think they either don't know the score or want to be one of the "too cool for school" kids in the valley, but lack the proper reasoning (I don't use that term for people with good reasons).