I got my last set of truck batteries from Batteries Plus Bulbs because it was the only place open I could find that had them in stock at the time, and I was actually pretty happy with them. They swapped the batteries for me for free. I think the batteries may have been about $175 each plus tax. Les Schwab would install for free too but I would bet their prices are higher, albeit probably less than the dealer with the service fee. Honestly I think a dealership service department is generally only good for warranty work.
One area where the diesel trucks are unavoidably more expensive than their gas counterparts are battery replacements, and unfortunately I tend to only get about 4 years out of my batteries before I start having trouble.
