Got this from their Twitter Page
http://twitter.com/#!/threadless
Some t-shirts are on sale as well (check $5, $10)
Shipping is capped at $6 if you order more than $50 worth.
/firstpost
MODS: It is a repeat of http://www.ozbargain.com.au/node/53673 (however, previously expired, and this includes $5, $10 t-shirt sale)
EDIT1: For some reason I've revoked my own post. Fail!
Everything on Clearance is low on stock. :(