Schwinn Stealth 1000 batteries

I just got a Stealth 1000 on ebay (new in box but a 2007 and batteries lasted less than 5 short trips so I assume they were more than a year old). Do any of you buy batteries online, where, and what's a good price? MonsterScooterparts has them for $120 plus $26 shipping. Does anyone know if Batteries Plus carries them and if they're any good. Any info would be greatly appreciated.
Pat