It was never priced or stated that it would have cost associated with it. The press release just said it was coming to BF Heroes in July, nothing about it was ever said that it would cost a thing. Jumping to conclussions, internet, entititlement etc...

The Kotaku post pointed out that clicking the notice took you to a page purchase Battle Funds, BF Heroes currency. Pretty much any banner on the BFH site wants you to purchase BFs, that is how they're making a return on this game.