Breanna Clemons, 26, of Bismarck told The Grand Forks Herald, "As we speak, I have over 200 bags."
She is asking $2 per ounce but says she is mainly trying to help mothers who cannot nurse and whose babies cannot drink formula.
"If someone were to inquire, I would pump it and store it, so it would be as fresh as possible for them," she said.
So far, Clemons, who is married and has two young children, has had no takers.
The Human Milk Banking Association of North America discourages free-lance selling of breast milk.
"We don't recommend casual sharing of milk from unscreened donors," said President Jean Drulis.
She said the organization screens donors for HIV, hepatitis and drug use. Milk banks pool the milk of several donors and pasteurize it, Drulis said.
Clemons said she is willing to meet with customers, have them visit her home and let them review her medical records.