What is the ruling on buying allergy-specific milk from sellers who offer it at a cheaper price than pharmacies, knowing that they obtain it for free from the Ministry of Health (whether they are eligible and sell the surplus, or obtained it by forging documents)?

Individuals are permitted to sell milk subsidized by the Ministry of Health if its owner acquired it legitimately and it exceeded their needs, provided that they did not deliberately collude with the doctor to dispense an excessive amount. If the dispensation is based on the infant's need, it is not permissible to request more than what is needed. However, if it is a fixed quota, it is permissible to receive the full amount and sell the surplus. It is forbidden to obtain it through falsification. You may buy allergy milk from individuals unless you strongly suspect that they obtained it through falsification.