Greets to everyone at webhostingtalk. I would like to say first that you guys have been very helpful in the information that I have gathered.

This is my question. I am thinking about reselling web host but I was wondering how domain registration works. What I mean is does my provider registers my clients domain or can they directly register their domain on my web site? What about the cost...some places offer domain registration for this much while others offer it for that much. I am not sure if I am being clear. So basically, can I do domain registration right off of my website if I am reselling or do they have to go through some domain registration?

If this wasn't clear, just let me know and I will try to rephrase the question again as best as I can.

Thank you very much!!!!

You can do either but I would register the domain for my client rather than make them go somewhere else to register the domain and you may lose that client if you don't offer them that option.

I think you weren't clear enough.
Do you want to offer domain registration on your site?
Or do you want to know affordable places to refer your prospective clients to?
I think you want to know if the host you're reselling for provides the domain registration for your customers. The answer to that is two fold. If he is a registrant's reseller, he may very well have the capabilities to. But, he is not your exclusive remedy.
Again; maybe you need to be more clear. ;)