There was an offer to get Windows 7 for free, but it's over. You could try asking Dell if they will still offer you Windows 7 for free, but it's probably too late.

Free Upgrade From Vista To Windows 7 Sony Vaio

It is quite understandable that most people deny to install Windows 10 from scratch and rather they prefer to upgrade to Windows 10 smoothly without risking the protection of their data being wiped. It is indeed a straight forward task but still it is thoughtful to write a guide on how to upgrade Windows 7/8 to Windows 10 effortlessly. Sep 25, 2019  I've heard if you buy Vista you get a copy of Windows 7 free The Windows 7 Upgrade Option is available through participating PC manufacturers on selected PCs and through Microsoft on qualifying purchases of the Windows Vista packaged product. The Windows 7 Upgrade Option applies to Windows Vista Home Premium, Business, and Ultimate editions.

I've heard if you buy Vista you get a copy of Windows 7 free
The Windows 7 Upgrade Option is available through participating PC manufacturers on selected PCs and through Microsoft on qualifying purchases of the Windows Vista packaged product. The Windows 7 Upgrade Option applies to Windows Vista Home Premium, Business, and Ultimate editions. Your Windows 7 upgrade will be to the comparable version: so you'll get either Windows 7 Home Premium, Windows 7 Professional (the upgrade to Windows Vista Business), or Windows 7 Ultimate, respectively. The Windows 7 Upgrade Option program runs from June 26, 2009 through January 31, 2010. Individual manufacturers may choose to offer the option for a shorter period on their PCs. Offer details, prices, and upgrade delivery methods will vary. For details for new PC purchases, please check the manufacturer's web site. For purchases of retail packaged software, please go to the Windows 7 Upgrade Option fulfillment site for retail packaged software .
If you qualify and need help getting your free copy of Windows 7 click here:
http://www.microsoft.com/windows/buy/offers/upgrade-option.aspx

Free Windows 7 Upgrade For Vista Users