If you're not "expecting" now, but want to have children, just go to BabysRUs and Target and see how much things cost.
- Diapers -- for 2 kids, over $100 per month
- Daycare/pre-school -- for 1 kid, full time $1500-1800, part time $800-1000
- Food -- Free for the newborn if nursing (use this if you can, but buy a high-quality breast pump to store milk in the freezer. Oh, yeah, buy a deep freezer too. More money)
- Open a 529. College will cost $1 million in 20 years. Or something like that.
Money Tips for New Moms - Alpha Consumer (usnews.com)