With visa on arrival, you will save at least 20% over getting a same one at embassy. There will be no consulate fee, time fee as well as no transportation fee to visit the Vietnam Embassy. There will be no postage fee as everything is done over email.
Visa on arrival is a Fast and popular way to obtain your visa to Vietnam. The whole process has only 3 steps: (1) Apply online for an approval letter and have them sent to your email (2) Show the letter at the airport and pay the stamping fee (3) Get the visa.