It would appear that a large part of the problem is the person's finances are in such bad order, they cannot afford to buy the diapers in bulk. Could the local church or community organisation not buy the nappies in the bulk and then sell them at the lowest item price possible ?

When in such poverty (and potentially from a less educated background) I know finding solutions is difficult. But this is where community should help. Having a baby is super expensive and super stressful, but there are some things which can help e.g. consider cloth diapers, encourage breastfeeding to avoid formula costs.

I don't know how much support someone like this gets. But I guess not enough.