An Argument was invalid

Worked for me. The steps I took are:
** on steam: **
- selected a different country to mine
- filled out my details
- changed country to mine
Then the shipping cost appeared.

However, this did not work for me on the website. I get the message "You will not receive physical goods for this transaction"

Either way, I am choosing to opt out as the shipping cost for me is 145USD!

I found the fix for me. If you live inside the United States, DO NOT TYPE OUT THE FULL STATE NAME! only use the 2 letter abbreviation.