Open sky has $6.00 shipping right now -
It's easy to sign up and fun to get the emails saying that you have a credit in your account.
They are one of the few sites that I know of that just give credit away.  I think I've gotten at least $10.00 a month from them since I've signed up.  This credit Does expire, so you have to use it within a certain time - but I usually find something "I just can't live without" :)