What’s the cheapest pharmacy in Houston?what can I do to lower my hospital fees?

I’m 20 years old my girlfriend (20 also) just had surgery that was 10 thousand dollars and idk what to do her pills where 150 at cvs I paid already because I don’t want her to suffer but where still in medical debt and I’m going to need to buy more pills for pain and nausea. I’m planing on paying the 10k by monthly payments but there should be plans to lower this or a different pharmacy where I can get cheaper pills. Someone pease help.