I just submitted it as a free site and it was accepted. May be i was given a preference because I had paid a bit to Yahoo Finance section for a small service.(Yes i had submitted from the same id from which i made the payment) ;)
i think link exchange with other website is the best and no cost .
i have 2 Pr website(http://www.vietnamfuntravel.com) and would like to exchange with all website and with all category to get more pagerank.