I've been using Linux since the mid 1990s and, except for playing games, can do anything that a M$ machine can do. Almost all Linux versions have a "Live CD" where you can boot Linux from the CD and play with it without disturbing anything. If you find you like it then you can install it on your hard drive and make your machine dual bootable, meaning you can choose which operating system you wish to run. Shopping for Linux is like buying a car, some people like Chevies and others will only have a Ford, etc. M$ is like Henry Ford, you can have whatever color you want as long as its black.
Two companies I have used over the years with no problems are:
CheapBytes -
http://www.cheapbytes.com/
OSDisc -
http://www.osdisc.com/
Both offer a wide variety of Linux at very cheap prices
Another even cheaper option is to download a Live CD ISO and burn it yourself.
Larry