This is the issue of travelling to Vietnam. There are lot of travel agent in the web. I choose those recommended in tripadvisor.
The travel agent charge from US8 to US15 and the visa cost you another US 60-80 (can't remeber the exact number).
Travel agent also charge you some value added service like "cut the queue".
I did not pay for this value added service when I visited first time. I need to wait for an hour in the immgration (for the landing visa). When I waited for my landing visa, i saw the travel agent took the passport from their guest to the official directly. So I decided to pay for this service when I visited 2nd times.
Btw, the so called "visa" we applied on the web is just a letter of approval / consent so that we can get the visa when we landed the airport.
If you have bno, you can use bno without visa that I was told by my friend.