Just tell them what you think is fair and reasonable.
If some doat is calling from Vegas or some other area and looking for something ridiculous low fair then forget about it. There is negotiation and then there is stupidity.
Then other thing is trading. Say some guy is looking for services but is looking for the low end range offer possible for cash and tickets. (ie 300 plus tixs to some sold out performance ie Circ de Soliel or some show or possibly hotel reservations.)
Just a thought....

Frankly I don't think you want to suggest negotiation as much as flexibility.  I.e. "In my local area I request $xxx for an hour and additional time is at a lower rate.  Travel over a half hour and provsion of a place to meet entail extra cost."

My English isn't that flowery tonight, but I think you can say very nicely that the basic time in home territory is so much, more time is les costly and travel is more costly.  If you use the word request and someone really wants to negotiate, beleive me he will pick up on that word and so so!  On the other hand, I take what a lady asks for at face value, and if it is our of my reach I just say, ah well, this just wasn't meant  to be.

I have seen your site, you are hot and all the stories are probably right on.  Yet, you are not in my league.  I am not a peeny pincher, yet, I do try and get what I (can) want for my money.
    I think if you were contacted by someone from LA like your example, and instead told that person to try and find some "friends" who would like to meet you on there own.  For example, that guy from LA posts here and says, "Hey, I contacted Heather, she is willing to drive here, if we make it worth her while!"  Now, instead of one "date" you get three or four, then you can talk about deals.  I don't think you should give your time away.  Hell, that would not make any sense.  But, I do think that some of the providers are WAY OUT OF THEIR MINDS for what they ask for their time!  If a guy can set you up with three or four dates, then you can work something out for all concerned, Right?  Some don't want FS (if you two hit it off and find each other "hot" and engage in anything based on your mutual attraction, that is) and might only want HJ, or HJ and DATY, or any other combo.  If you make a great deal with one guy, doesn't mean you need to do it with all.  Just ask that they not post anything to do with prices.  
    Referals, that is another way providers can make deals.  I will not ask for a cheaper price.  I would not want to "BEG" nor insult the providers.  If you spend time with aguy and "wrap" things up in less time than asked, give a small refund!  Nothing wrong with that.  Most guys would say for you to keep it.  But, the offer will go along way.  Just look at how many posts talk about the woman leaving before the time is up!  Girls, you can help yourselves and us by just being fair!  Work with us, we work with you and there will be more smiles all over the place!  Just MHO!  Thanks for your time.
The Footman

I'd just figure out what your time is worth to drive and get a hotel.  
ie: 300 for one hour
2 hours driving 100.
split the hotel
=450 for one hour

or:

500 for 2 hours, 100 for driving and you pick up the room.. giving choices seems to work best for me.
=600 for two hours

of course you can choose your own numbers LOL