I disagree with the premise of the question. The economy should be fairly secondary when considering having children, unless we are talking about extreme cases. I see many people in developed countries who do not have children or postpone having them indefinitely because they have to go on trips to upload photos to Instagram. It is better to be clear about the unity of the couple, the common life project, and if you have limited resources, you will manage. That is how it has always been done. Another thing is that if you have limited resources, do not be foolish and have 10 children; take precautions.
As someone who is from an underdeveloped country, you can't place the economy as secondary when talking about having kids. It's part of the most important things. In an economy like mine, you have to have different streams of income or a very large income if you're going to have a kid, because the government won't help you in any way. No free education at any level, inflation continuously on the rise, you have to find ways to provide your own electricity and other basic things the government should be providing for you, like water. You also have to consider the security. How safe will that child be? Will he be safe enough to and from school unharmed? each day? If you can't guarantee these things, I don't think you should have a child.