i have been stationed in beijing for a while already, trust i can give some advise to you.
in beijing, there is a quite a lot of escort service. people like me who have an apartment here, normally we would receive the "ad" once a week. indeed, i try quite a number of them. but for sure the quality is not consisent. sometimes you got a budget deal. sometimes u would simply slam the door and ask them to leave right away. and the most important thing is the girl is not willing to perform oral job here, and some of them are even a dead fish.
in regarding the price, brother doer's recommendation is the relatively the higher class one. i have tried and the girl is a bit better. however, for those i have tried through my own channel, the price is about rmb 500 per shot and rmb 800 per night. which sounds a budget deal to myself.
let's share more beijing's information together then!