Ebay pictures are a special case of photography. As a buyer, I want clarity over artistry. As a seller, I want to give buyers what they want with pictures that are flattering but don't hide significant flaws, and I want to do that quickly. Note, this also applies for documenting my collection.
My setup evolved, and I might do it a bit differently if I were starting from scratch or had different sources to scrounge from. I started with a cheap light tent that my wife found at a big box store, when I was mostly photographing watches. This could be easily replicated with some sheer white cloth and a PVC or wire frame. It came with lights, but they were inconvenient to set up in a way that gave the light I wanted, and the official background cloth that came with the kit was usually wrinkled enough to show in pictures.
The rest of the setup is not as necessary, but nice additions with stuff that I had already. The whole thing sits on a piece of 3/4 plywood bolted to an industrial super heavy duty tripod, probably a speaker stand. This lets me adjust the height while taking up minimal space. I had an old darkroom enlarger timer in my collection, I've started using it to control the lights--push of the button and the lights go on for about 45 seconds, then the timer resets itself automatically.