Mostly map packs have comprised the DLC for the Modern Warfare series, and Modern Warfare 2 continued the trend with its XBL-for-now map pack. However, DICE doesn’t agree with charging their players for ridiculously overpriced map packs, and has issued a statement which will satisfy all Bad Company 2 owners.
After the news of Modern Warfare 2 receiving a rather 
expensive map pack, DICE has announced they will not be charging for any of their map packs. Ever. Battlefield: Bad Company 2‘s senior producer, Patrick Bach stated:
We don’t ever want to charge for our maps and insisted to EA that this attitude was crucial when it came to keeping our community happy and playing together. We’re owned by EA but we’re still very much DICE.
That’s it DICE, just give us free map packs–hell, even reasonably-priced ones–and we’ll all stick to Bad Company 2, we promise.
