Conversational spanish lessions

So reciently I opened my preply account and I started giving online spanish lessions.

I ranged my price at 6$ and I see many different prices per hour 35$, 20$, 15$, 8$ ect..

So there is no middle price I could pick.

I have been active in spanish speaking, I am not a licenced tutor but I do have one year spanish course diploma, and I have been involved in spanish since I was 10.

I worked with my family in Medjugorje and I helped them with email/faks and everyday comunication with tourists since nobody from my family knew spanish.

I am 25 and I am medical student so I enjoy working with people, I am patient and I have big amount of vocabulary.

I am not shure what decent price would be since I do not have diploma for being a teacher but I do have communication skills and I believe I am excellent at conversational lessions.