I just tried to apply for a Vietnamese visa at the Consulate of Vietnam in Pakse, Laos. I was told that each visa is 50 USD, for regular (2 days) processing time. But no one could tell me anything about the stamping fee, which might be asked for at the border. The stamping fee is 25 USD, when doing an e-visa. All over Thailand and Cambodia I saw visa being offered at a much lower rate through agencies. What’s the prices I should pay? I hold a German passport.
The stamping fee is only for the pre-booked visa, which you get on arrival. Visas that you get in the Consulate, the regular sticker in your passport, do not need a stamping fee. You go straight to the Immigration counter.
Also, note that as a German citizen, if you are not planning to stay more than 15 days, and haven't used this within the last 30 days, you don't need a visa: you can get a 15-day visa exemption. This means that you show up at the border without anything, and get to stay for free for two weeks.