you press cancel and press a figure close to what you like. she may frown or laugh. just smile back and remain firm and cheerful.
after several minutes of exchanging figures, a compromise is made.
and the transaction becomes a pleasant social exchange.
my friend dindo showed me how to do it. as a matter of fact "my friend" was the first thing he told me to say when i haggle. and the calculator is the medium of translation and transaction. many of the vendors do not speak english. but it does not bother them if you gently touch their arm or hand to press on an amount. they have no hang-ups with touching so long as it is not the head! it is rude to touch someone else's head. and the haggling can take 10 minutes at least. it also pays to know a reasonable price as the vendors tend to overprice. sometimes, the reasonable price is 30% of the price she gives you. they are generally honest but they are wily. it really helps to say "my friend" as you show the numbers you pressed on the calculator.
you may encounter snooty vendors who may shrug you off. i have heard of tourists waved off by vendors who are tired of haggling.
vietnam offers good quality silk, bags (many are copies though), shoes, lacquer work and other handicrafts. their paintings are good and cheap investments also.
so, there, the metro male has learned the art of shopping in vietnam.