Some times, some people, want things, they can't afford ( and I'm one of those people) . EG : designer bags, fancy cars, expensive holidays, latest iphone.  All you have to do is prioritise  and save up. Easier said than done 
There are people who do charge too much : Barristers, cosmetic surgeons, plumbers in London, dentists for implants 
Whatever you charge "The Price Is Right"   

I have had so many idiots ask if I do 15 min quickies even though it's clearly not listed on my profile! I then put it up but for ?80 just to throw filter those type of men out, because half the time they're the cheapskates asking for a discount. One said he only had ?40 and if he could do an appt for 15 mins even though I charge ?100 for 30 mins.

Then one asked for my hourly rate and said I was too high-end for him. I don't even charge that much for 1 hour, especially for London and considering how much it costs me to travel down. Idiot clearly did not read my profile properly!

If you can't afford it, you shouldn't go shopping in Harrods, Bond Street or Fortnum and Mason   

There are some men, who look at the costs of their each punt in a certain "unhealthy" way.  Cheaper the rate is the better, and to their eyes, the ladies, who offer these "cheaper/cheapest" punts are far more gorgeous than others at "higher end" (in fact, average, going rates that everyone else would charge, nothing more).   If they did spend an average/or higher price on someone else, they try to boundary push to get the most of the booking by overstaying.

You need to be careful who you are seeing.  On AW fdks, you could see which guys went to these local vulnerable looking newbies, who charged next to nothing for their custom, whilst these punters would be spending loads of money anyways on these ladies (e.g. frequent, short visits).   They think they bagged a bargain e.g. cheap pussies and keep going back to these "affordable easy to handle (vulnerable) ladies".   They probably like to pop as many times as possible for a set amount of cash.  Sometimes, 10 visits on their 30 minutes booking seem like a great "value for money" and they spend X amount without realising that they spent far more money over a set period, let's say, over 3 months.  They are not getting any richer by this type of punt.   Also, ethical aspects.  Know your customers.

On the other end of the spectrum, there are men who'd rather spend an average price, they may even spend a longer booking.  These guys aren't competing with other guys as to how many time they popped last week, this week, I'm the No 1 of the whole pack, yeah!!! etc.   Have fun, mate.

In your case, this man probably saw a much cheaper price on offer elsewhere.  He still chose to see you.    Why doesn't he go to a much cheaper lady/ladies, instead?  If someone said you were expensive whilst the price is average in the area, I won't bother seeing the man.  He's essentially angling for a discount.  In fact, it's the same thing, quite disrespectful. 

My favourite was when I declined someone attempting to haggle (he'd already arrived and parked up, not yet in my flat), and then he had the nerve to get angry at me and accuse me of being money hungry 

  that would also make my day but it's never happened to me as yet sadly

I had this yesterday had a 60 min booking and he gave me ?10 more than my hourly rate and said I think that is the price a hour with you is worth. Its the first time it has happened though

I've had the same thing happen in the past and it's so kind.