You are in for a RUDE awakening.
Personally I don't think the costs of children are what you think about ahead of time or even what is in these articles.
One thing depends if you are goin gto stay home or not.
Frankly I do not spend much on the kids as a whole, they are not expensive at face value with food and clothing (my kids are 3 & 1).
Formula and diapers are huge in the beginning. I pretty much breastfed both babies, even working and all, but a can of formula is ridiculous - maybe $10-$20 - I don't even remember - just pricey. Even if you intend to breastfeed it might not work out so you have to include it in your budget. I used formula as a supplement after the first few months. The first one was barely on formula, and the second one was on it for 6 months I believe - had much more issues. Diapers are pricey too - count 4 years - kids train late these days.
For us though the really expensive part is healthcare. When we decided to have kids we were paying $200/month at most for our coverage. Today we pay $900/month for the same plan with a family of 4 - and it doesn't seem to be going down - 10-40% increased evey year. Plan ahead for it, I Wish I had any idea... (Higher premiums mean better coverage though - entire pregnancy, deliver, infant checkups cost $300 at most out of pocket)
My oldest is 3.5 and my dh has not worked in 4.5 years or so. In our original plan he would return to work in another few years. This seems less and less likely and prudent as time goes on. Today he can not even find a minimum wage job to supplement our income. IT would be great and help but no one will hire a guy who stayed home 4 years to raise kids is about what it seems. ??????
These are some of the pricey factors of kids. On the other hand, the extended family spoils them with toys, their clothes are 2nd-hand, they will go to public school, they are happy to play make-believe and go for walks to the park. This part of raising children may be less expensive than you imagine. But look at the bigger picture of how you want to raise them in the early years and how some of the costs of the bigger picture will be. A spouse out of work 5-10 years costs a lot more than just lost wages I am finding out. Daycare around here is $1k/month per kid at best, but depends on the area - not so much in lower-cost areas.
This is not even getting into what if you can not get pregnant and start pricey medical procedures, or alternately you have a problematic pregnancy and take unexpected time off work, or a sick child, or a disabled child that needs care. All things to plan for the best you can. These are the things to really think about.
Good Luck. Don't want to scare you. But truly the more you think and plan ahead the better off you are. Just some of the things I wish I had foreseen a little more.
All that being said too I wouldn't care how much they cost, they are priceless.
