I get my batteries from Tractor Supply Co. Labeled Exide right on the label, and as stated above, way cheaper than Wal-Mart. The group 24 in my car was $69.99, and they honored the pro-rated warranty portion of the battery that was in the car (which I did not buy, and was from Rural King---but it said 'Exide' as well, so they honored it). The credit they gave me was $24.50 toward the new battery.

All I did was ask, I even made it clear that the battery was in the car when I bought it (the car). That customer service gem garnered them another battery purchase when the wife's laid down, and the purchase of a chain saw. lol
All the other parts stores wanted $90 or better for a comparable 2 year battery (and I can assure you that probably no one but a local farm store chain would honor the pro-rated warranty without receipt), and no one does the pro-rated warranty periods anymore, so saving money won the day.
I have also purchased batteries from Rural King before, with good results. Also sell Exide batteries, also cheap. Ymmv.
