Sam,
If you don't want to spend any money and aren't in a hurry to get things going, I would advise you to download every free book you can find. Also join as many internet marketing newsletters as you can.
This free information will give you some starting knowledge. Then when you are ready, you can look into buying what you will need to get the full picture. (free stuff rarely gives you all the information you need to know)
You don't specify exactly what you do with computers in your profession, so find material on the net that has to do with what you are doing if that's what you want to make money from.
Good luck.
Georgina Stath
http://www.beyond-short-story-writing.com