MacBook Pro 13" Unibody Mid 2009 Teardown
Actually, the battery will cost exactly the same amount as any user-replaceable battery--$129. Apple will likely offer (like they do with the iPod, iPhone, and 17" MBP) a battery replacement program that only charges the cost of the battery. They will have to take it away from you for 24 hours, but they certainly aren't getting more money from the new setup. Just setting facts straight.