Whatever you do, avoid the Wall Street Inn Hotel near Soi Twilight.
I made the mistake to book one night there two years ago (fortunately just one night). There are ants everywhere in the hotel. In your bed, in the shower, on the floor, hell there were even ants at the plate with the poor breakfast they served me in the morning, which I of course gave back to them in disgust. On top of that rude staff and they informed me they charge 500 baht for taking guest to my room. Worst hotel I have ever been to anywhere in the world.