New Multi Boxer! Got some questions!

Hello everyone! I've read a lot already on multiboxing and I have the general idea of how to perform with it. So heres my question. I got my crap 1 core 3.06 Processer, 1 gig of ram (getting another this week) 8600 Geforce video card ect ect. As of now im using the RaF which Im lvling 3 mages. So heres my questions, is multi boxing not multiboxing without 4-5 accounts? and what Im I looking at for a comp set up? (the cheaper the better). Just trying to see the general input of multiboxers and seeing what you guys suggest for a first time boxer. The biggest question I have is, is it worth it? I love the sound of 1 shotting people in pvp and taking on groups of people/soloing instances, but I'm not the most well off guy, I can afford it but It will be a large investment, the 75$ a month, plus new comp parts/computer (if i 5 box). I know of a lot of you swear by it, but if any of you could give me some general input that would be great. But from what I've seen tho its really fun! :)

I doesn't matter how many you box. some people enjoy running two characters, some three and four, but the majority move up to Five (and beyond sometimes).

I started with two and have gradually moved to five ( I still run two's in Sunwell dailies)

It all boils down to how much you can afford per month (and the additional hardware costs in some cases)