As the title says.

I am unsure of the going rates for Control panels, and I need to know the best choice for 10 liscences.

=THanks

I think part of it depends on if you want to pay more upfront, then no monthly, or rather pay monthly with little to start. Meaning you could get 10 cpanel licenses for the cost of 2-ish full no-monthly fee licenses, but you will end up paying more in the long run (support included blah blah blah, I'm not trying to start a debate on the issue).

In the subject you say 10 domains... in the post you say 10 licenses... Do you run 10 servers? Or 10 websites?

If you run 10 servers I would recommend something like
H-Sphere or Cpanel/WHM.... (there are many more good ones out there too)

If you are running only 10 websites, on your own personal server then I would suggest a free control panel like webmin or web-cp.

Hope this helps.
~Mike

what about plesk... 30 domain license for $199

Worth it, or should I stick to Cpanel?

It would be 1 server, with up to 30 different sites on it :)