The Windows 7 price is basically legit, but since everything else seems not to be legit, I'm not putting a lot of stock in that site.
Actually, I should mention that it is showing the retail packaging for Windows 7, but it's not specifying that they are actually selling an OEM copy (since one of the entries says Windows 7 Ultimate 32 bit - retail packages of course come with both 32 and 64 bit disks so the distinction of the software package being either 32 or 64 bit is not necessary). I know other, more reputable companies do the same, but given the prices shown on the site, it makes me think there is something more going on. It's not outright false advertising, but it is certainly misleading.
I would not recommend downloading Windows 7 from any other site than the Official Microsoft Sites.
Additionally, it's always best to make sure you have a genuine version of Windows 7, this will entitle you to recieve updates and support from Microsoft with Genuine Advantage.
"Microsoft Genuine Advantage programs, including Windows Genuine Advantage, help you determine whether or not your copy of Windows is genuine. Genuine Windows software is published by Microsoft, properly licensed, and supported by Microsoft or an authorized partner, giving you full capabilities, access to all the latest updates, and confidence that you are getting the experience you expect. Microsoft continues to invest in education, engineering, and enforcement in order to more effectively combat software piracy. It’s part of Microsoft’s commitment to help protect its intellectual property and to help you avoid problems before they happen."