yes less than 4 millions.
you can find some on Giang Vo ( the streets running parallel to Kim Ma which goes from the Horizon Hotel to Lang Street).
you can find some made in China (big white square machine) that do the job but pretty noisy. But on that street there is a duty free shop where you can buy up to 6 days after you've entered vietnam. You need to bring your passport and the white paper.
In that shop they sale a "Delongui" one that are pretty good, quite silence and that can even be used as a small heater in winter.
I heard you can also find them some where else but don't know where.
But definitely a must have in Hanoi. It avoids having your leather shoes or jacket turning green!!! and your bedsheets smelling during winter time.
hope that helps
cheers
