In RLD's (and I am fully in favour of FKK's beating them 100-1) the most important thing to remember is to do ALL YOUR BARGAINING outside of the room BEFORE you go in. Be specific about what will happen, what will not happen, for how long and all that sort of stuff.
If you want 30 minutes with her taking ALL her clothes off, you taking ALL your clothes off, She Blowing you WITHOUT a condom (specify real blowjob where you can see her lips taking in your member) followed by coverd sex (again real sex) in multiple positions. Time is to be filled out even if it takes two pops.
If she agrees to all that for a price before you go into the room, chances are she will nto rip you off. Many will not agree, they use every loophole you leave open.
Go to an FKK and don't waste your time trying to filter out the 10% good providers in RLD's out from the scammers.