On my last trip, I stayed at the Regency Park (Soi 22). Paid £6 via Priceline.co.uk - total steal.
Got a room with a huge king bed, clean and nice enough. This is a Mercure hotel (part of Accor) and apparently owned by the same folks as the Novotel Lotus. Normal rates seem to be around B1500-3000.
No problems with girls - arrived one night around 1 am with two cuties.
