I've used seeking.com over the years with some success. In the last 12 months it seems that some girls have been looking for dream guys who would pay over $1000.
The more realistic ones are uni students who seem to expect on average $600. Some ask for 700 to 800 but you can negotiate.
In all but one case, only one girl had her own place so I have to also fund hotel rooms, around $200.

As mentioned above, with SB the meetings are usually for 2 or 3 hours so the average per hour is favorable when compared to RnT and FS venues.