WASHINGTON — Many public colleges and universities expect their poorest students to pay a third, half or even more of their families’ annual incomes each year for college, a new study of college costs has found.

With most American students enrolling in their states’ public institutions in hopes of gaining affordable degrees, the new data shows that the net price – the full cost of attending college minus scholarships – can be surprisingly high for families that make $30,000 a year or less. Read more.