Teaching Children English in Rural Cambodia

Hello, I am Anson and I am trying to afford a trip to volunteer with children in Cambodia. I have always volunteered whether it be at a hospital, with animals, or in a charity shop. I have never volunteered abroad and I was hoping to put myself to use in Cambodia. I believe that this will be a lovely insight into the life of a traveling doctor, which is what I aspire to be. Vaccines are very costly as well as airplane tickets. Please, any amount will help. Thank you.