Patient assistance programs (PAPs) are run by pharmaceutical companies to provide free medications to people who cannot afford to buy their medicine. Each pharmaceutical company have their own program and decide the general requirements - such as patients with financial hardship, without any third party coverage, patient not qualified for Medicaid, etc.
There are organizations such as RxAssist, NeedyMeds, Partnership for Prescription Assistance, etc. offers a comprehensive database of these patient assistance programs, as well as practical tools, news, and articles so that health care professionals and patients can find the information they need. All in one place.