>Can you buy human breats milk

Yes - though it's a caveated "yes". In some places, selling human milk is illegal - but sharing it is not.

Not legally. There are underground exchanges and black markets, etc. La Leche League can hook you up.

Yes, legally.

Human milk can be obtained from a milk bank with a doctor's prescription[1] and sells for $3-5 an oz.[2]

[1]http://milkbankne.org/receive/

[2]https://lactationmatters.org/2013/11/08/why-is-donor-milk-so...

Interesting! We had looked into this before and found that it was difficult/impossible. I'm glad it exists!