there is a thing called link exchange program, u use other similar site's banner on yours (or somesite related to you) and in exchange they market yours. as well, try selling few products on eBay, as well giving link to your site. (like writing, if you cannot find what are lookign for, try it at my shop
www.abc123.com), F*** eBay as if they have rule that your site has the product but in hihgher price (I hate them for that, Blood Suckers) - Ian/Praedor, sorry guys for getting tooo offensive in slang dont kick me out of forum
anyway, where were we, right!!, to tacke this situation, dont put those things on eBay which you already are selling, like u can sell t-shirt of say Windows, but keep other designs and other O/S seperate on your web site.
2nd thing, if u have knowledge of Metatags (are in header tag information of the HTML page), optimize your at leat two meta tags information wisely, that are, keywords and description. search engines are BOT/Spider operated, ythey'll pick up your site once uploaded with good meta tags etc).
use this link frequently in your site (tell your mates/friend).
and now before writing this line, I have actually visited your site (usability status), its cool . put commas (again comma thingi I was discussing with Paedor), in keywords. and make them little more, I couldnt find any difference in your description and keywords. optimize it well.
also put somewhere (as if its not there) product feedback, what kind of logo/words you want to see more in future (things like that), as there is no AMD

, Awww, I find people going for stuff like that are more AMD fans, make some t-shirts of ATi, nVidia (look for copyright issue, as I dont think they'll mind, unlike playboy did sue many people, A** H****) this doesnt show my particular interest in playboy specially

, but I'm representative for MSc E-Business, therefore went for a case studies related to copyright infringment for playboy + many - now u got it. dont think am interested inti stuff like that, I dont have even got any gf. can U imagine ??
anyway, again coming to ur point. and also give a clear shot of what is written on the shirt (as in some cases i couldnt read clearly).
go on forums like this is , you'll get your at least 15% audience from forums. which will be ur potential clients and word of mouth advertisers (depending on product quality u are offering).
I'll write more a if I come with some other idea, as though Inhad deeply studied cyber marketing, personely I hate it, as i'm more into web site usability and Web Based Business Modelling Strategies.
Cheerz!!