In my opinion, if you are thinking about starting a cafepress shop it would be in your best interest to create a main domain page website. It gives a little bit of a personal touch to your shop along with a more professional look.
Just because you may not be html savvy that does not mean you can't create your own website. I am pretty ignorant when it comes to html but I made a simple homepage with a domain name for my shop. I not only give information on what my cafepress shop is about, but I also add various pages to the site including a links page and information on becoming an affiliate of the store. The possibilities are endless and having a domain name is much better and easier to remember than having to type out cafepress.com/blahblahblah right?
You can use your imagination and be creative with your website and give people a reason to keep coming back! You can advertise sales that you may be running or new products that you have designed and added to your store. You can post up various shirts or products that you have in your shop to entice people into looking at the actual shop location. You want something that is going to catch the viewers eye and keep them going straight to the shop where they can purchase your products.
You can get a lot of ideas by looking through other cafepress shops and their own homepages!
Again, the link to my homepage is: daftcreations