I bought a Personal Edition of Linux 7.3 from Redhat.
I presume that Linux is a free product.
Can I sell that CD copied to a new CD and sell in the market.
Is there any other factors I need to take care of?

I'm planning to buy lot of other products from Redhat as well when I can sell this.

Redhat is a collection of programs-- each with their own license--
each with their own rules.

Linux, and *most* Linux programs are released under the Gnu Public
License ( http://www.gnu.org/copyleft/gpl.html )

Which says:
---------------
1. You may copy and distribute verbatim copies of the Program's source
code as you receive it, in any medium, provided that you conspicuously
and appropriately publish on each copy an appropriate copyright notice
and disclaimer of warranty; keep intact all the notices that refer to
this License and to the absence of any warranty; and give any other
recipients of the Program a copy of this License along with the
Program.

You may charge a fee for the physical act of transferring a copy, and
you may at your option offer warranty protection in exchange for a
fee.
---------------

It *does not* say "you can sell it for the cost of the media itself
with NO added cost".

Red Hat talks about licenses at
https://www.redhat.com/licenses/rhl_7-3_personal_us.html?location=United+States&

With all due respect, the answer given by the researcher is wrong.

If you want to find out what you can and can't do, read the license
agreement.  Here it is for Linux Personal Edition 7.3:
http://www.redhat.com/licenses/rhl_7-3_personal_us.html?location=United+States&

The bottom line is that Red Hat software is a bundle of programs and
applications. Some of them (such as the basic Linux operating system)
can be freely distributed, while some of them (specifically those
produced by third parties) cannot.  If you merely copy the Red Hat
discs and distribute them, you will be breaking the law.

Really the comment section is bit worthful, otherwise I would have
made a wrong decision. Thanks for helping me a lot a lot, but I'm not
still clear and satisfied with the answer. Let me wait for it.

    Thanks to jes5199-ga   &  mvguy-ga