I think I pay like $2.35 a filter for a napa gold, and you can usually find oil on sale for $9-11 for a 5 quart jug. It's worth the 5 minutes it takes me to do, and rather than make a special trip to get supplies I pick a filter up on my way home since I drive by napa, then snag the oil the next time I'm in town. I'm not terribly particular with hitting the mark on oil changes.
