Hi bro, I'm a Malaysian posted here since last month myself. For me the main obstacle is communication, although I'm chinese but I cant speak mandarin or cantonese well so I use English.. it's very frustrating sometimes!
From what I observed, stuff here is definitely not cheap especially those branded ones. When I convert them back to MYR, they cost about 10-20% more in my country so let's not imagine the price when you convert them to SGD
As for food, if you choose to go to those fancy restaurants then it will cost more but if you know how to go to those moderate chinese restaurants it's pretty affordable.
I stay near the Airport (Hong Ha) and the apartments there cost about 700-1200+ USD per month with 4-5 rooms. Not sure how much it will cost if you stay near the city though ... ?
Anyway, enjoy your stay in Vietnam. Remember to bring plenty of condoms! Oh and another thing, becareful about bringing girls back to your house. If they get caught after 12am in your house you will be fined 10mil Dongs. So find a permanent live-in gf and register her to stay with you
