Many possible ways. (1) Buy the "RedHat" or Mandrake CDs from Linuxmall (http://www.LinuxMall.com), or Cheapbytes (http://cart.cheapbytes.com/cgi-bin/cart )--last time I checked, "the unofficial" RedHat GPL was US$2.99 or something like that for a 2 CD package + shipping and handling. They will mail you bare CDs. You get no printed manual, no support, no boot diskette, but the price is right, and the manual and tools to make a boot diskette are on the first (installation) CD. I purchased several packages from "Cheapbytes" and they always arrived fast, were of good quality, and there were no problems with my credit card charge (the authors have no connection to "cheapbytes" whatsoever). (2) Buy the boxed "official Red Hat" or "Mandrake" from the same place on the Internet or from your favorite software supplier; prices start at around US$40--you will get the printed manual, e-mail or telephone installation support (60 days?), the boot diskette, additional CDs with "bundled" commercial applications, and perhaps other goodies (free updates?). If your time is worth lots of money, you may opt for more advanced technical support at higher price. (3) Copy the installation CDs from your friend. This is perfectly legal and ok--Linux is free. If you have a Linux CD, don't be shy to loan it to your neighbor. (4) Check your library, local bookstore, or http:/www.amazon.com. Several Linux handbooks come with an attached CD containing a full Linux distribution. This is a good way to start with Linux because it is definitely a good idea to have a nice Linux handbook. With Linux' countless utilities, I need a handbook all the time. The drawback is that the books often include versions of Linux which are quite dated. Perhaps consider the "official" Linux with a handbook? (5) Visit a Linux "installfest" when one is organized in a place near you. Local Linux "gurus" will install Linux on your computer free (bring the computer) and you will likely be able to get a Linux CD too (why don't you bring some empty CD-R to the fest?). Check for the Linux User Group on the net to see when the nearest to you plans an installfest. Good way to meet other Linuxers too.
Here is a more comprehensive list of places to obtain Linux CDs with their location, so you can find something near to you (after B.Staehle) : http://www.ixsoft.de (low price CDs in Europe); http://linuxservice.de (another source in Germany); http://www.polo.demon.co.uk/emporium.html (The Linux Emporium); http://www.linux-emporium.co.uk; http://definite.ukpost.com/ (Definite Linux Systems); http://www.mallind.demon.co.uk/ (GPL + official distros); http://www.amush.cx/linux/ (GPL distributions in UK only); http://www.linux123.co.uk/ (GPL + official distros in .uk); http://www.kihi.com.au/bowtie/ (Bowtie Software - cheap CDs in OZ); http://EverythingLinux.com.au/ (cheap CDs in OZ); http://www.lsl.com.au/ (cheap CDs in OZ); http://www.arles.ns.ca (official distros and BSD in .ca); http://www.affinity-systems.ab.ca/ (Official distros - hardware in .ca); http://www.warpedsystems.sk.ca (GPL + official distros, custom built system CA); http://www.softcopy.on.ca/ (cheap CDs in CA); http://www.libranet.com (Libranet Linux Vancouver, BC, CA); http://www.linuxwarehouse.co.za/ (low cost and official in South Africa); http://linuxcentral.com (Clinton Township MI 48035); http://www.lsl.com (Chesterfield, MI 48047, USA); http://www.cheapbytes.com (Lodi, CA 95241, USA); http://www.infomagic.com (Flagstaff AZ 86004, USA); http://www.tummy.com/krud/ (Fort Collins, CO 80525, USA); http://www.pieceby.com/ (Hudson, NH 03051, USA); http://www.linuxmall.com (Aurora, CO 80046-0190, USA); http://www.linux-now.com (Clarion, PA 16214, USA); http://www.xcomputing.com (San Francisco, CA 94134, USA); http://www.ccsoft.cc/linux/ (Santa Rosa, CA 95401, USA); http://www.storeanywhere.com/ (Brooklyn, NY 11235, USA); http://www.linuxcomponents.com (Owings Mills, MD 21117, USA).[an error occurred while processing this directive]