The thing you want is simply called a "background canvas" and they come in all colors and patterns. They also sell "background paper" that comes on very wide rolls
Are you doing table top sized shots? Many times these are done on translucent plastic with a strobe mounted under and a pair (a key and fill) of strobes mounted over. You'd also want some kind of modifier on the lights, something to soften them A "softbox" or umbrella. That's the basic setup for a shot used in a catalog but for eBay you don't want anything so professional looking. Poor photography make it look like you aren't a professional eBayer.
All that said, for eBay wait for an overcase day, take product outside, put it on a white beach towel and shoot it. Use Photoshop to select the towel and then adjust the brightness "way up".
One more thing: Trying to make a "high key" image That's where the background is "white out" will be REALLY hard if you only have one strobe because that one stobe will be closer to the subject than the background, even a white paper background will look dark. For eBay you can just fake it in PS