BattleForge Points are one of two types of currency in the game. The other being Gold.
You can get BattleForge points either by selling cards at the in-game market, or purchase them online, for example, from the BattleForge website or the EA Store. Optionally there will be a BattleForge Point Box available in retail. This costs 19.99€ and includes 2000 BattleForge points. You can purchase BattleForge points in smaller denomination online (500, 1000, or 2000 BattleForge Points).
The current price of BF points is $20 for 2000 BF points.