Whoever wrote this must not have kids. I wish it were that inexpensive to raise a child. Estimates for raising a child to age 18 is on the order of 250 – 300K. That’s 1150-1400 per month.
It can be that inexpensive if you want it to. Case in point, I know a family who live on one income (well under 6-digits) who have 4 kids and a house almost paid for in Mira Mesa. They all are turning out to be smart, happy, and obedience. So, yes, it can be that inexpensive if you want it to. It can cost $10k/month/kid or $200/month/kid. It’s really up to you.