I have been staying at the Pradipat Hotel during many of my trips to Bangkok, and sometimes I stayed there for over a whole month. It is a very unpretending, dated, a bit shabby kind of hotel, not suitable for everyone, but liked by the Thai and Middle-East clientele.
On the ground floor, behind the reception, they have rooms that they rent "by the hour" (you know what I mean), with parking space in front of the room door and a heavy plastic curtain that hides your car from the view of others, very convenient for some intimate and discreet meetings. They don't discriminate anyone based in their sexual orientation.
A funny thing about this hotel is that it was designed to drive your car up to your room, with ramps and wide corridors, wider than some sois in Bangkok; they don't use these ramps anymore, but as kind of store rooms.
Some of the rooms are like small apartments and you can have as many people there as you want. Say that you are a group of five or six backpackers and you want to find a hotel for less than $5 per night per head, with air-cond, full en-suite bathroom, living-room with fridge, two TV sets with channels in English, two double beds and a big couch (enough for a couple) in a location near the Sky train and with girlies and gay bars around: this is the place.
If you go with a Thai friend and he/she negotiates the price of your stay, putting the room under his/her name and paying in advance, you can get it for half the advertised price.
Forget about the breakfast or restaurant in the hotel, try the many coffee-shops, street vendors or family-run restaurants along Pradipat Street, or try the Food Court at the nearby Big C hipermarket in Pahonyotin Road, only 10' walk from the hotel, where you can have a decent meal for less than $3.
On Saturday and Sundays you can walk along that road to the huge Chatuchak Weekend Market, a 30' stroll, depending on the many stops you make to look at the stamps, coins, amulets, old magazines, etc..., before reaching the actual market.