I seem to recall there were some services that charged a one-time small fee in the late-90s / early-2000s basically for that reason. But in the past 10 years most seem to have moved to requiring a mobile phone number as the hurdle instead. The idea is that it has some of the same deterrent effect for bad actors, since coming up with a steady stream of unused mobile numbers costs a nonzero amount, but produces less sign-up friction for legitimate users.