Are you sure it s oxacillin? This is an antibiotic which is generic and should be very cheap. What is she taking the drug for? If it is something else and absolutely necessary, sometimes the drug companies supplying brand name drugs will offer plans to help with costs. You can check with the company manufacturing the drug (not the pharmacy). Her doctor may have other suggestions. Check with the Medicaid office to see if she might be eligible for assistance there. Many communities have supportive programs for elderly that may help. Check with the senior centers in her area.