First, the battery was from eBay, normally they're about $22-25, but I found an auction for a battery with 2 charge cycles on it for $15.

Also, any idea how to check if the logic board is replaced? I would like to know, but I haven't had any problems so far. Great laptop for light / medium use, but can't do much heavy lifting on it anymore... I've been using air display to use it as a remote display / keyboard / trackpad for my 11" i7 Air. Gives it full 1650x1080 res, and I can use the pro's keyboard / trackpad to control the air. Pretty awesome!