Are you an eBay member now? Have you gone to an eBay class, taken the ebay tutorial or researched your product? If not, I'd hang around on ebay for a while and see whats available and what people are setting their prices at. You'll also need to research the current listing fees and such that you will be charged. If you're just getting started, I wouldn't open an Ebay Store. I'd just list your item and see how it goes. Just go to eBay and type in personalized. You'll come to a page that shows all types of groups. You'll notice specailty services amoung others. There are also listings under custom bookmarks and personalized christmas ornaments. My sister has purchased custom birthday bookmarks and a ton of other personalized stuff off of ebay: birthday posters, personalized embrodered sweaters for little ones, website building services, rubber stamps, painted tiles, I could go on and on.

As far as the brushes and elements, I'd have to agree with Kathryn about selling those on ebay. But you could always list and see how it goes. If the demand is on that site, you'll find out and can go from there. Good luck.