If your rent is below SGD 2500 then you pay half a month's rent for a year lease and a full month for a 2 year lease.
If your rent is over SGD2500 then you pay nothing, the landlord pays his agent half and your agent half. Some agents will advertise that they don't charge tenants and they negotiate that all electrical problems such as AC are fixed for free in the first month but that is standard.
It is against the law for an agent to represent the LL and the tenant. What you find here is that a
property is advertised many times, once by the landlord's agent and then by anyone who feels like it. If you call them they will set up an appt and go with you and sort of just appoint themselves your agent. AFAIK it is illegal for somebody who advertises in this way to refuse to give you the LL's direct contact.
We've done a few moves, with and without agents. Here we had the option of using one that the company preferred. He's ok but not fantastic and the way it works here unlike the states or UK you keep your agent for the entire contract. If we have problems with the house ( a window fell out, the kitchen collapsed from damp, water heater exploded) both of the agents trek down, have a look and the LL's agent organises repairs. Not all of the contractors we have had in speak English so having the agents here has helped.
As far as school and houses go, if you need to use the bus don't assume that close means a short bus ride. Our house is 4km from the school but because of the bus route (small bus, only 8 pick ups) they wanted to pick up our 14 and 5 year olds at 6.45am for an 8.20 start. I think most of the buses are run by the same company and if you ask they will give you a route, a map and estimated pick up/drop off before you sign for a house. Kicking myself on that one.