no offense but those designs wouldn't have taken very long to make - and all you did was make the image then set up a standard cafe-press affiliate style store - it'd look a lot more professional if you got them printed up yourself and made a site yourself and sold them on it via paypal or something
If you can't afford that, you can buy t-shirt transfer paper for about $8 for 10 sheets and plain t-shirts for $2 on ebay, then design your own website on free space... that'd still be a lot more likely to get people's attention and respect than just composing some vector images and sending them to cafe press
Even if you did that, I'm pretty sure you STILL wouldn't be allowed to advertise it here, its counted as spam.
Good luck with your t-shirt business if you are serious about it, follow my advice and you might do well, my record company used this method for band t-shirts when starting up, and we made a killing
