What is a reasonable pay or salary for online copywriting freelancers?

It really depends on the field. Niche writers can command a lot more per hour than most general writers, and it also depends on their years of experience, training, and successes. If you go hourly, you'll be looking at a minimum of roughly $ for a decent copywriter, but $- if what I'd call average here in UAE for web site text. Of course, you can probably find help cheaper elsewhere, but in this industry you really get what you pay for. 

It depends on the type of writing, place of employer and time, besides, the number of essays per day

There are websites (e.g. www.freelancers.com, www.guru.com) where people advert their services (and obviously others look for freelancers). There you can check freelancers' profiles and payment which they expect, maybe they can advise you also.

his\\her writing skills and what they can deliver in a short amount of time 

It depends on your level of expertise and quality of your work. Most often, too, your work ethics have a bearing on how clients pay you. It doesn't matter whether you have been doing the same job for a long time or have just begun. What the clients are interested in is the quality of your performance.

Many thanks for inviting me to answer this query.

Refer to your question, to give a clear answer there are many points to be added  otherwise it is not possible. such as  type of subject matter, type of Consultant who is doing the job, quantity & quality of work. As I know some of the in-house Consultants are getting $ to $ per hour at the same time you can see in the local market it could be $ to $ per hour.Thanks 

I fully agree with the answers been added by EXPERTS................Thanks.

It depends on the effort, time and circumstances surrounding

Thanks for invitation

Actually i do not know