purchase a headstone for my Mother's grave

My last goal was to visit my mom’s grave and I did that today. I was not happy when I got there because there was not a headstone to mark her grave. My aunt was supposed to take care of this when my mom passed away, but I guess she never did. I mean it’s been six years and I didn’t know that this had not been taken care of. I guess I really feel worse since I visited because now I feel like it’s my fault that there is still no headstone. If I had went more often I would have found out that my aunt never purchased the headstone.
I talked to a lady at the cemetary today about headstones and they are outrageous. I never knew that they cost so much. I told her that I would not be able to do anything until after the holidays, so that should give me some time to do some research on my options.