I've read that some people go to Khao San and pay about 20 USD to a travel agency in order to obtain a tourist visa for Cambodia. That's ok with me, but I don't know the exact date when I'll enter Cambodia, because I will travel through Thailand and Laos before entering Cambodia. Is that a problem? Is any travel agency ok or would you recommend a particular one?
I should have mentioned straight away that I mean to enter Cambodia from Laos.