Sharks: 100 Euros buys you 30 minutes of OWO and sex
Artemis: 70 Euros buys you 30 minutes of sex, with an extra 20 Euros if you want OWO
Bear in mind that in both places, if you've gone for the standard 30 minutes your time will end once you come.
I don't know how much extra you'd have to pay for anal, facials, an hour session etc as I always go for the standard service.