I was admitted to grad school and had no grants or scholarships. I paid for it out of my own pocket. The school took my money with no problem.
Yes, you can get a scholarship before applying and then use it at whatever school you get admitted to. There are a couple of scholarship books at libraries and bookstores. The scholarships for college and grad school are listed. Some have a time limit during which they can be used, so don't think you can win a scholarship and sit on it for five years while you think about grad school.
Check with the financial aid office at colleges for more information.
NEVER pay anyone for a list of scholarships. There are books and free web sites that list them. Here's one site:
Scholarship Search - Find Scholarships Online Free - Grants, Internships