haha guess this will be me first post than ^_^ ever on the board
It all depends on your style of clothing really, ninomax is a well known store in saigon, if thats where you planning to go. it's basically like the american version brand name of Gap. it isn't a leading name, but it a very well known and for reasonable price.
But you can find so many nice clothing, in random stores, it doesn't just have to be anywhere, or go for the fake versace etc... stuff hihi
if you're in saigon, the street... Nguyen Trai
is a very popular street to go buy clothings, (but note that its more exspensive on that street than some others) alot of the singers of VN singers tend to shop around there
just my 2 cents ^_^
i stayed there for like almost 3 months, and i came back only like 4 months ago

have fun while you're down there, enjoy it,
if you're into the beaches check out vung tau
I"ll be planning to go soon again too haha