Why do Collages send out spam mail?

After taking the PSAT and getting good scores in each category, I was expecting to get some kind of useful information from collages when I checked that box to allow collages to get my information. I was very surprised to see my inbox flooded with hundreds of spam emails from collages halfway across the nation from me, that clearly did not match the majors and information I submitted, and even worse, they were all in the same similar style, all led to the same generic website, www.*collage name*-info.com or something like that, and they all tried to give me some stupid product. I just don't understand what's in it for them? If they are giving it to me for free, it can't be to sell products and make money can it? And if they are trying to win over prospective students, I can't see how sending out literally 3 - 4 spam mails a day to someone will make them look better.