Substitute/Alternative to Camera Bag?

I have a digital slr camera with extra lenses and accessories. I was looking into buying a bigger camera bag to hold everything, but they seem so expensive. I was wondering if any of you use anything else instead of a camera bag to tote your equipment. I had considered a nice diaper bag.

An old back pack should do fine.

when i traveled for two months....I just got several little, padded make-up bags and a large tote...Like the small vera bradley bags. i put my lenses in the make up bags, then put it in the tote with my camera. It was more conveient than a camera bag, because it wasn't so bulky and because it was under my arm and against my body, it was safer.

try an insulated lunchpack ,you know the soft kind .
also check thrift stores people size up often.

A diaper bag or an old backpack are excellent ideas, just make sure your gear is not banging around loose inside. When I travel abroad to areas where crime is more likely to happen, I use an old bag and dress to blend in so people are less likely to notice that I have an expensive digital SLR and lenses with me.