ftp://ftp.redhat.com/pub/redhat/linux/7.3/en/iso/i386/
You can go to this link for the redhat 7.3 and download the 3 iso image files.
If you want mandrake than go to the mandrake website and choose the download link. They are all free. Downloading Mandrake is the same as RedHat, you need to download the iso images and burn them to cd.