just spend $50 or less to get cheap used pair then upgrade with new drivers, specially tweeter (from taobao, very cool drivers, such as:
http://s.taobao.com/search?initiative_id=staobaoz_20140415&js=1&q=%B4%F8%CA%BD%D1%EF%C9%F9%C6%F7&stats_click=search_radio_all%3A1