There is a bookmark in the browser, just open it and there it is. I also went to Ebay and made a shortcut/bookmark on my home screen by touching the star with the +, it will then ask if you want it in bookmarks or on the homescreen, pick one and then it will ask you to name it then your done. Hope this helps!
But what would an app do that the website doesn't?
This is a bigger question than it looks. Apps, as they're implemented right now, provide a better user interface/experience when interacting with a touch screen - albeit at reduced functionality. While I agree nothing is wrong with using the browser to do a lot of things that Apps could/have replaced on other platforms, Apps do tend to be more user friendly. Also, consumers are currently conditioned to want apps and thus find it a bummer if there isn't one.
Well I detest the Facebook app resident on the Playbook simply because of its limiting factors. I tried it a few times but my "user experience" was anything but "friendly". LOL
I might try an ebay app but, in the meantime, I'll stick to the fully functioning website.