babies don't need to cost a lot.
a few of those all in ones, bath them in the sink, resuse stuff, second hand pram off ebay, change them on an old towel on the floor, etc.
weaning - lob them a bit of what you're having (suitable stuff obv.)
toys - well, from years of experience, they tend to prefer wrapping paper, boxes, pots and pans and cheap tat from the pound shop.
They're as cheap or expensive as you want them to be, basically. you can make do and mend, buy second hand, etc or you can get them the whole kit and caboodle.
there's really very little you HAVE to have and of that, even less that HAS to be brand new.
I can only think of car seat and cot mattress, although I am sure there may be a couple of other bits.