While I do sometimes think about all the things I would do differently than my parents to raise a child, it is just a thought exercise after all. I don't have the discipline or finances to raise a child - I definitely fall into the selfish group of non-parents. I'm still focused on helping myself, and until I get that right, I can't be worrying about creating new people to care for.
Children are relatively cheap to raise - unless they have issues :D At least in my opinion, they don't have to be extremely expensive at least.