If she is taking standard diabetes medicines like metformin, you can get it for free at various grocery/pharmacy stores like Kroger (https://www.krogersc.com/drugs). Also, diabetes medicines in the US are not very expensive if you are taking generic versions. Either way, you do need a doctor's preskription for it. If you have a US doctor that can prescribe you, that would be the cheapest and the best way to get it. If you do not know a doctor, let me know, I work with a doctor, so I might be able to help with the preskription part.