I volunteer to help with VBS at my church, and I've done mostly music throughout the years. The curriculum and music has varied, with some years it being pretty simple, like campfire songs, and some years it being a pretty aggressive pop style praise music that has me kind of rolling my eyes, and yet doing all the movements, trying to get the kids involved. We always have 5 different sections, one being games, another craft, story, snack, & music. The snack isn't always so great, but I think that depends on who is running it. I mean last year, ick, they used spray cheese! And we made little animals with hotdogs and pretzels.
I have pleasant memories of my days in VBS as a teen helper. My 14 year old actually wanted to help this year, but we were out of town when it was going on. There is definitely a Bible component in most curricula. There is a Bible verse every day, the songs are about the Bible verses or the stories, and we'd read a Bible story and say a prayer at the end. But, yes, it's pretty inexpensive, so we get a lot of kids just because of that.
Maybe you can ask and check out the curriculum being used. In the past we've used Augsburg Fortress. There is also Cokesbury, and my kids have done the K4J curriculum at the Catholic church too. They aren't religious, but they enjoy it anyway.