On the checkout page, is there a blue box asking you to confirm your address? Tap/click on it to confirm and let the page reload. It should take off the shipping charge.
(Please note: I don’t work for Woot, I just volunteer to help out here on the forums.)
Are you signed in using your AMZN login?
If your using the totally sucky app, are you confirming your receiving address?
Oh crap … I’m so slow this morning
I like that you think it’s just this morning!
Sorry, couldn’t resist. 
Heh 
The good thing about losing my grip on things is I get to meet so many new people each day!