Redistributing RHEL

Hello, I install web and file servers for customers. Some of them asked
for RHEL for free because it is based on GPL software. I did some
research and I think one can install RHEL for free. Red Hat is based of
applications and software based on the GPL, which means that you need
to release software based on it with the same license. You can sell
GPLed software but you are free to redistribute it at will and you need
to provide source code.

Please let me know if I'm mistaken.
Thanks,

.