You need to change your external IP... just route your connection through a proxy.
If you have a dynamic IP, it'll change on its own. Ask your ISP if that's the case. If not (you have a static IP like me), just get a private proxy (~$1 per month) or use public ones (free). There are plenty of threads about this on BHW already, as it's pretty much a necessity for doing anything remotely gray or blackhat.
IMO, You really only need a VPS if you're going to be blasting emails 24/7 or something that requires automation and anonymity together for long periods of time. I just use private proxies for most of my work, and it's going well so far. If you only need a new IP for manual browsing, I'd just look up a public proxy before each time (I use automated scrapers, but there are lists on the forum you can use) and use a preconfigured setup like the Tor browser (slow and banned in a lot of places), or the proxy switchy app for chrome, or the proxy button in firefox. Lots of options.
A big company like eBay probably isn't going to look very hard behind your new IP so I wouldn't worry too much, but you need an elite proxy, meaning it will not identify itself as a proxy, and appear as just another browser (though it depends on just what you were doing...)
