i think everyone would reconmend an ASUS eee netbooks for that kind of price,heres what i would buy:
its $318 but it can do all your needs nicely and it has 160GB which should be enough for your music and documents etc,it has 7hours of battery life too
http://www.amazon.com/ASUS-1000HA-10.../ref=de_a_smtd
if not theres this 14.1 inch gateway laptop which is used:
http://www.amazon.com/gp/offer-listi...condition=used