Try clicking on the link on your post. It leads to a page saying "Thank you for visiting Newegg.com. We apologize for your inconvenience. The page you requested is unavailable."
EDIT: If we're to use OEM copies of operating systems as a guide, OEM modems are "tied" to the motherboard you're using; you only have a license to use that modem with that motherboard, so once the mobo goes kaput, you technically can't use the modem anywhere else. That's why it's cheaper.