They generally will require students interested in these funds to complete the financial aid process anyway to make sure they receive all aid to which they are entitled. Aid is usually in the form of a tuition waiver or reduction, or a cash stipend to help defray educational and personal expenses. Graduate schools often, but not always, require students receiving aid to work as researchers or teaching assistants. Students must meet the sponsor's criteria in order to receive a private scholarship. The criteria may or may not include a student's financial need.
Private scholarships can be very competitive, i.e. many applicants for a few awards.
While many internships are learning experiences where students only earn college credits, some pay a cash stipend. Many also lead to employment opportunities during the summer and upon graduation. Coop advisors help you secure a job that fits your interests. You definitely should apply for everything for which you are eligible and that interests you. If you receive need-based financial aid from a college and a private scholarship, you will be required by your college to inform them of the scholarship amount.