You have to get a hotel that is GF (Girlfriendly). If not they could charge you as high as 3,000 thb (like Holiday Inn eg.). Where have you booked ?
L/T or S/T is diff from p2p. S/T is probably around 1,000 - 1,500 thb. L/T aprox. 2,000 - 3,000, depending if you r a handsum man or not ? How hot the girl is and so on ? Also consider the barfine around 300 - 600 thb.
Try the search for GF hotels.