Don't forget the 15 - 18% tax on top of the room charge.

How long are you planning on staying? There are hundreds of serviced apartments in BKK. Monthly rates on a studio seem to run ~ 2,000 THB per night (averaged) in the nicer facilities Centrepoint , for example).

If you want to drop down a notch, or two, and are only looking for a few days or a week, you can look into properties like Omni .

I've visited and or stayed at both (Centrepoint Wireless and Omni) and thought that they were fine.