Especially if you have to purchase the produce, canning doesn't make sense economically these days. Here are a couple of reasons why I still do it:
1) Some things you just can't get at the store. Homemade grape juice and applesauce are so much better than the store bought variety. It's worth the extra effort, at least at our house.
2) If I don't factor in time, it really does help with the family budget. I'm going to be home with the kids anyway, why not use some of that time to do something productive - and hopefully teach the kids to be productive, too!
3) I love having a garden, and gardening automatically leads to canning.
4) I have lots of wonderful family and neighbors who love to give us their extra fruit - how could I say no to that?