The currency
One US dollar is roughly 25,000-26,000 dong, which makes every price tag look enormous: a bowl of pho is 40,000-60,000 VND. Notes run from 1,000 to 500,000; the polymer notes are colour-coded but confusing at first.
Count your change carefully and learn the 20,000 vs 500,000 distinction fast; they are different colours but easy to mix when tired.
The 500,000-dong note: Vietnam's largest denomination, worth roughly $20. Notes run from 1,000 to 500,000; the polymer series is colour-coded but confusing at first. Photo via Wikimedia Commons.
Cash and ATMs
ATMs are everywhere in cities and towns; withdrawal limits are typically 2-5 million dong per transaction with a local fee of 55,000-100,000 VND. Withdraw larger amounts fewer times.
US dollars and euros exchange easily at gold shops and banks in the big cities, often at better rates than ATMs. Keep small notes for street food, taxis and markets.
Tipping
Tipping is not traditional but is increasingly expected in tourist areas: 10% at upscale restaurants, small change for guides and drivers. Bargain first, tip after.