Pencil2Print: I don't want to sound flippant but it's best if you use the search function here on the forum and read as much as you possibly can about CO2 setups before buying anything. That way you'll have most of your questions and concerns addressed and won't have any doubts about what you need specifically. It's not too confusing once you've read up.
As far as DIY goes... it's how I started and I think it helped me learn a lot about CO2. It's a heck of a lot easier than people make it sound. Even if you get a fancy setup with a solenoid and such, I recommend starting a DIY system just to get the hang of it all. I had a lot of fun doing it.