One estimate pegs the cost of the campaign at $30 million, which could break the record for a U.S. Senate primary in Massachusetts. Subscribe to WCVB on YouTube now for more: http://bit.ly/1e8lAMZ Get more Boston news: http://www.wcvb.com Like us: https://www.facebook.com/wcvb5 Follow us: https://twitter.com/WCVB Instagram: https://www.instagram.com/wcvb5/