Any digital camera will do. I'd choose a name brand, just for the support and warranty. Lighting will be more important than the camera. If you are selling small items, buy or make a light box and purchase some lights. There are kits available on eBay for $50-150 that include a light box, lights, and sometimes a tripod or other camera support.
I wanted to purchase a camera that enables me to take mainly still images and some close up shots outlining detail. Starting an Ebay Shop and will need to take lots of various pictures of the one image.