Kids will take all you have...
... and just when you've given what you're absolutely sure is your last ounce of effort, they need a little bit more.
Oh, you mean money. Well, if you believe what you read on the Internet then you could start here:
http://www.babycenter.com/costofchild/
College is the big, scary, long-term project. I've heard the story of the 17-year-old who made a deal with his parents. If he graduated from high school with honors, they'd give him his college fund and he'd never bother them for money ever again. They agreed, he made it, they turned over the money, he ran the numbers on FIREcalc, and he skipped college to become the world's youngest ER.
Others feel that college is best appreciated when it involves personal work & sacrifice-- from the kid, not the parents. I have mixed feelings on that approach but I can certainly agree with parents saving up four years at State U and letting the kid make up the difference. In our case, we've been saving $100 week since the first week.
As far as raising babies, there are two schools of thought. One is "I'm going to have lots of kids so I'll use everything to its max and I'll pass all this hardware on to my eldest for their family." In that case you might check your parents' inventory, or else you'll want to pay through the retail nose for new and get 2-3 decades out of it... and you can stop reading the rest of this post.
We're using the "Goodwill & garage sales" approach, which started with buying (*gasp*) used baby furniture. Now, before the Consumer Product Safety Commission jumps into this, our first purchase was a subscription to Parents magazine. Within two issues we were experts on all the horrible killing machines, I mean baby furniture, in existence. I think our insurance company gave us a free car seat but we did just fine on used cribs, carriages, strollers, and toys at half-retail or lower. Frankly, cardboard boxes & blankets work just as well.
We don't break out groceries separately but that cost is all over the map. If Mom is breastfeeding then it's not much more than your normal grocery bill. If you're using formula, well, some kids eat more than others. Ours started at a quart a day and quickly shot off the charts. Diaper consumption was pretty impressive, too, which I vaguely remember was in the neighborhood of a dozen a day. (Don't start with the disposable vs cloth debate, it's about the same expense and it's less than 1% of the landfill. Do what makes you feel more virtuous and don't bother us with the details.)
I think the rest of the expenses are lumpy. Baby prep costs a lot until they arrive, then you're too tired to go anywhere so things are cheap for a while. After a couple years they're quite mobile so expenses start to rise, and then expenses absolutely explode when kindergarten & school supplies merge with sports & social activities. If everyone's working then childcare will be a constant until the kid is out of elementary school. And we have yet to experience the teen spending years, where we'll probably cough up even more but won't be permitted to watch it being frittered away. (Eh, kid, get a job.)
According to my records, as of yesterday we've spent $61,259.78 on our almost-12-year-old. That doesn't include groceries, which would probably add 50% to the total. Nor does it include the college savings. And it doesn't include a number of trips to America's finest franchise juvenile-dining facilities.
The majority of that, $25K, was for nearly nine years of childcare. Another $3K was for toys, but it doesn't include gifts from grandparents and indulgent aunts/uncles. Another $2500 was for various short-lived sports (gymnastics, dance, t-ball). $10K has been sucked into the school system-- Kumon, school supplies, bus fare, lunches, & field trips. Hopefully you can avoid $500 for six months of hula lessons and another $9000 for three years of horse lessons (dressage-- and we don't even own a horse). Three years of Scouting sucked down another $1000. The rest of it was spent for a good purpose but ended up in the "I'm too tired to care so it's miscellaneous" data-entry category.
Our kid has been extremely healthy and we've only had one broken wrist. Good luck with yours.
We've just been quoted $4200 for what I'm told is fairly straightforward orthodontia. We're doing it without dental insurance, which is a healthcare rant for another topic.
Overall I think that parenting is better than childlessness, but I've belatedly realized that it's a life sentence without parole. My brother-in-law and his wife are perfectly happy to be childless (while spoiling our kid) and I know several sainted couples who have raised a baseball team of their own and then take in foster kids. Of course under that bell curve your expenses will vary widely.
So plan & budget all you want, but it won't survive the first labor pain!