In the Geylang red light area, there are lots of cheap hotels renting out rooms for 1-2 hours at a time (all around S$10 per hour, some minimum 2 hours). Hotel 81, Fragrance Hotel, etc....and their branches.
In Geylang, outside the red light area (small lorong numbers), there are also some short time hotels. Like Four Chain Hotel, near City Plaza.
At Still Road, there is Malacca Hotel (more expensive, but spacious rooms).
At the Balestier area, there are also many cheap hotels - Hotel 81, etc.
Hotel 81, Fragrance Hotel, etc....also have branches in other places like Chinatown (opposite Chinatown Point) and Katong.
If you are expecting an over-nighter and want something a little better....book Garden Hotel (near Scotts Road area) through the internet (do a google search and compare prices). Should be able to get it for less than S$120 per night. Spacious rooms, includes buffet breakfast...and they've even finally fitted their TVs with remote controls.

OK....don't tell anyone I told you all this ok?
