Center56 - Do you want to buy shirts in bulk and have them printed for you and you ship them out, or do you want a print on demand type store? If you are wanting to buy shirts and print them, I`d start by looking in the phone book at your local options. I always support local and small business when I can, and they usually have much better, more personal customer service and more willing to give `tips`.
For greeting card printing, you can look in to local specialty printers in your area. Not Kinkos style, but specialty printing houses.
Like you said, you do have a lot of options. For online companies, many of them supply samples. I`d get samples, and make a list of pricing and then compare them to find the one that most closely fits your criteria.
As for building a website, if you don`t know how to do it, definitely hire somebody. You have to look professional if you want people to take you seriously. Your sales will show it!
My husband has shirts at CafePress and Zazzle. Zazzle does a much better job on black shirts. Cafepress just prints it on, and it fades off on black, but Zazzle puts a white layer on first, so it`s nice and bright. However, he sells a lot more on Cafepress by picking up browsers there.