Arrived at Noi Bai International Airport, Hanoi, Vietnam at 21.00 (local time) and got our visas on arrival (stamping costs $25 per person). Indian passport holder requires an approval letter from the Vietnamese Embassy prior to arrival, the cheapest online service being this one.
At the airport, we got USD converted to Vietnamese Dong (VND). We then, quickly grabbed a burger and a donut and hopped on a sleeper bus to Sapa.
Recommendation - Sapa Express
We had booked Sapa Express bus with an airport pick up at 22.45 hours (costed $22/person for roundtrip bus + $5 for airport pickup).
The currency denominations are very high and may cause confusion, so here is a tip :
They do not say the last three zeros, so a lakh is only said and counted as a hundred. It would be much easier if you calculate 135,000 as 135 instead of looking at notes as a 1 lakh, thirty thousands and five thousands.