I am planning a 4 days vacation in Vietnam. It is quite easy applying for a Vietnamese visa at its embassy in Singapore. 2 photos and 2 copies of forms. But surprisingly, the total cost including service fee is much higher than VOA online. S$105 for one person single entry. whereas the online VOA application only costs around $45USD including $25 USD stamping fee you need to pay at border control.
It seems the agent who collects documents on the site makes S$70 for a single applicant. Quite impressive.
Next time when I want to revisit Vietnam, I definitely will save a trip to the embassy so that I can get half the price for the visa