I wouldnt go over $350 per hour.
Akira is at that price point and she has an extensive menu.
Akira is also very pretty and all natural.
I doubt Forence Yi is better, so there is no point in paying double for a sex-worker who is no better. It depends on your experience as a hobbyist and your overall level of self-esteem. If you have low self-esteem, you will tend to pay more for girls that arent worth it. The guys who book Florence at $600 per hour, obviously suffer from an overall lack of confidence.
She has been around for close to 10 years, and her vagina would be well-pounded by now. Basically, like a used catcher's mit. She must be well into her 30s and if I recall correctly, she has small breasts and no ass to brag about.
So, yeah, she is basically worth $180 - $200 max, but is asking for 3 times that much.