coreyants i was there for a week and only spent a few hundred £ incl. hotel (although we had a group rate thing) it's quite cheap except alcohol ask lonelypuppie @hellboy247
Singapore is super expensive compared to the rest of SE Asia though.
coreyants Do Bali in Indonesia and do some of the southern Thai islands. It's probably more dangerous in Vietnam than either of those two places. I can set you up with some places to go and shit too if you did Indo, Thailand, Singapore, etc.
You can literally live on like $10 a day in Thailand. Easy. Food, accommodation, transport. It's cheap as balls.