There is a lot of fun with very little budget. One suggestion is taking SG subway "Circle" line. It links all popular tourist spots. e.g. Nicol Highway station. Come up from there you will reach the beautiful riverside. You can walk along and reach Marina Bay.
Clubbing --- SG have many popular disco but expensive too.
SG is tropical country. Food safety is important. But we do have street food e.g. Maxwell food centre and the Telok Aryer Market at Raffle Quay.
Maxwell food centre sells famous chicken rice and local disk at HK$20
Telok Aryer is beautiful place. You can google it and many pictures from it. It sells street food and dinner around HK$50 per head.
visit singapore one time only and it was first time going there but the experience was fantastic but everywhere is boring unless you try to explore it, of course if you are rich everywhere is like heaven