Hello wakwehu01,
It is our understanding that there are only three places a general retail consumer can make a legitimate digital-delivery purchase of a genuine stand-alone product key for Office 2010. Those places are Microsoft's online store, Dell's online store,
and HP's online store. (Microsoft's online store is fulfilled/administered by Digital River.)
We can absolutely, positively tell you that there are NO eBay or Amazon Marketplace sellers authorized to sell you any sort of digital delivery Microsoft products.
Looking at the site you mentioned, the company claims to have their address on Branson Rd in Dodge City, KS. Well if there is a Branson Road in Dodge City, it's news to Google maps. It's also very clear that the writer of the web site is not
a native English speaker, casting further doubt on their implication that they are US based.
IMHO a total scam.