Are there ATMs in the main towns of Vietnam?
Yes, there are ATM’s in all the main towns. Sometimes you may have to search for them but in almost every town there is one - Sapa included.
Warning: Some of the ATM’s have recently been reported to eat cards. Have a backup with you, or when you find one that works for you, continue to use that one.
Tip: If you are traveling to Vietnam during Tet, take out enough money to last you the week. Many people will pull out all the money they need before heading home. There have been times where all of the bank machines in Hanoi have been emptied.