Ofcoz is a high jump, imagine, SGD600 you might get a common room which is smaller(maybe a maid room still price is depend on location), without toilet, >SGD900, you can get a master room which is abit bigger and with you own toilet. basically is like your own small world in the master room, so the price is much higher.

So let me share with you my experience of finding room on what you need to take note of:
-Room rental cost(does it worth the price you paying for? normally within walking distance of MRT would be higher)
-Any agent fee and how much?
-Does rental included PUB?(this is how they address electric bill and water bill)
- Aircond(optional, if don't have can ask if owner provide fan for the room without ceiling fan)(sometime you see your room got aircond doesn't mean you can use, you need to ask)
- Internet(optional)
- what other utility provided?(e.g:water boiler,washing machine)
- cooking allowed?

this is my experience, might not applicable to all, you can take as reference if you want. normally you just ask room rental included what and they will give you all the answer already.
For my experience, i never met any arrogant agent before, all quite nice. they don't want waste so many times to layan you as they got alot customer so you give them your criteria they will look for you, you noneed to rush them, useless one. You can view the room, why not.

hopes this help.

you are talking about cover charge ? Not too sure about cover charge but normally a bottle of liquor like whiskey, vodka or VSOP cost around S$300 in top clubbing place, which let you admit 3 people/bottle.

I dunno bout cover charge coz I never club alone, ever. Also never drink beer during clubbing. Maybe S$30-$50 + 1 free drink ? SGD$300/3 = S$100 per person bro. Where you wanna go ? St James or Clarke Quay ?