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.
I tried various different backgrounds--smooth cloth, fuzzy cloth, cloth draped on its own, cloth glued to plastic sheet, cloth glued to posterboard. Wasn't happy with any of them. My current setup is a piece of blue posterboard. Doesn't look great in person, looks fine in photos. The downside is that it gets dirty easily. I'm going to experiment with coating the next one in clear spray on finish. To get the corner curve the way I wanted, I cut open a couple of steel food cans, then cut each can into 1/4 of a cylinder and glued the posterboard to the inside radius of the cans. The cans make a small radius without creasing, giving more useful space in the tent. I like blue, but no matter what color I chose it would be a fairly medium shade so it doesn't require compensation in metering. (This is especially true if your subject is relatively small,
With my old DSLR, it was hard to get low noise and enough depth of field while handholding with the lights I was using. For a while my solution to that was to borrow my wife's mid-grade point and shoot--its small sensor gave more depth of field at acceptable visual noise levels. Eventually I covered 3 sheets of foam core board (craft section of Walmart) in LED strips from Amazon. The sides were about 40% covered, the top as close to 100% as I could manage. This gives ample light for even my old DSLR. The lights are powered from a 12v power brick from a thrift store. (Side note--a new mid-grade DSLR has less noise than a 10 year old entry level)
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.