UK University Students Email Addresses and Mailing List

I want to market a UK based university student website to UK students. I am looking for a database of email addresses which i can send emails to, advertising my website. If you dont have data for students I may be interested in males/females aged 18-22. Please let me know the quantity of addresses you have, cost per thousand, where you got them etc I have selected the lowest budget as I want to pay much less than this amount per 1000 addresses thanks