@flowmon, @Macau81:
As far as I know, the price you pay (upfront) consists of the room price + the price for the service.
For 1 hour you will pay a total of 1900b, I think for 90 minutes it would be 2100 or 2200, and so forth. This price does include everything, no need to negotiate any extras, except maybe a tip which is up to you.
Look up numerous previous reports, like this one:
http://forum.sex141.com/eforum/v ... &extra=page%3D2