YIKES!! This morning I tried to create a $4.47 media mail label on Pirate Ship and it said it was going to charge me $2,181,288.53!!! Fortunately, it recognized this was an error and blocked completion of the transaction. Customer Service says they are aware of the problem and are working on it.
For future reference, you should not pick Space X as the carrier. 
Why that’s piracy!
I have been notified by Pirate Ship that the problem has been fixed (though I have yet to test it).