I can't say this for certain, but based on reading the item description, I don't think that he's describing something legitimate. Here's what he says he's doing: "Please understand you are buying software that was downloaded from Microsoft Volume License and burnt to a dvd's, it was then labeled and sealed."
Volume licenses are sold to companies and universities for use within those companies/universities. Many companies take part in the Home Use Program, which also allows for employees/faculty/students to purchase our applications for a reduced rate for personal use. In either case, you have to be working for (or a student at) the company/university to be able to take part in it.
Frankly, the whole description is pretty weird. He's quoting a bunch of stuff from Windows Office (such as anything about the "Fluent user interface", which is the official name for the Office for Windows Ribbon). All of his descriptions of the apps are for the Windows Office 2007 apps taken from elsewhere, not the Office:Mac 2008 apps. The description also quotes from a Mac Mojo blog post from February 2008 about the file format converter for Office 2004, which is irrelevant to Office 2008. Plus he types MAC instead of Mac, which always just annoys me.

Even leaving aside the legality of what he's describing, getting so much of his description wrong doesn't make me feel like this is the most reputable of sellers.
There are plenty of reputable sellers out there (including the Apple Store and Amazon) that are happy to sell you legal copies of Office 2008. You're going to pay more than $75 for it, but it's going to be an actual legal copy of the suite.
Regards,
Nadyne.