You can actually get free or almost free computers and software. A lot of people tell me how they can not get the computer going because they either lost system or do not have it to set their computer up. In some cases they would like me to duplicate some commercial media. I let them know I have something better for them. I would think that if you are able to use the web by reading this page you can get to other sites. You need to go to http://www.ubuntu.com and sign up for a free operating system cd. They will mail it to you for absolutely no cost to you. They even have instructions on how easy it is to use and set up your machine.
You say you do not have a computer. Your covered also. If you live near or in a city big enough to have a computer’s user group, I would find one. Usually but not always they have used computers for the taking. I know I have picked up two in the last month for special projects. There were still plenty left. Friends and neighbors who are always upgrading are likely to be benevolent with their old equipment. Be good to them. I have acquired some equipment from divorced spouces because they did not want anything of their ex around. That has happened twice for me to get free goodies. Anyway there are also a lot of thrift shops. school systems, and some computers shops that sell computers real cheap. Now that people are becoming more aware of the internet, these sources are drying up. I am not too keen on buying a computer off the internet, unless it is from reputable name brand company.
On getting spare parts, I do not do it without owners permission, but the garbage heep has good stuff too. There are so many techs who throw away perfectly good equipment for no reason. I guess they thought it was defective or unusable. I like to refurbish old machines like some people do with old cars. So the heeps are a gold mine to me. I can usually get the discarded items working in some way.
I was talking about the user groups earlier. So if you do have a problem with one of these old systems, you can get limited free help from them. I shrug when someone tells me that they can not afford a computer. I have given you just a sketch of some tips to having your own system. Good luck.