My friends recently (well October) signed a six month lease for a 1 bed furnished apartment, the
condo is new and pretty much empty hence them getting a 6 month lease fairly easily, their budget was in the 3 - 3.5k range and I dont think they went above it.
The condo is Parc Sophia on Adis Road, dont know who the agent was but they found him on the internet.
If your thinking of serviced accommodation, we stayed at One North thru LMB housing for a month when we first moved to Singapore, a nice 2 bed was around 5k per month and was (at the time anyway) the most economical while still being a nice apartment.