If you are in a tournament but didn't pay for skins at signup, follow these simple steps:
1) On the main tournament page, click on tournament in question.
2) Click the "Register Now For…" button.
3) Click the "Edit Registration" button.
4) Type your name and hit continue button.
5) Near the top, click on the blue link that says "Edit your registration instead of filling a new one..."
6) Click on the actions menu and select "Edit Registration"
7) Click "Next" button on bottom right.
8) Under "Additional Quantity" change 0 to 1 and hit the next button.
9) Select UNITED STATES under "country" drop down.
10) Enter payment info and click "Pay" button.