In the days of the EX:Ruby and Sapphire set I bought sapphire and ruby theme decks and one of them had a blank card instead of a holifoil card like the other one. I don't know what it means but the card still had a border but nothing inside.
If you find the right buyer, up to 30$ I hear. But it really depends on who's buying. The only way to know for sure is to put it on ebay and see how much it goes for.
