Can you upgrade from vista to windows 7 for free?

Short answer - Legally, NO
Cheapest solution is upgrade version, or OEM version.

Windows 8 Pro Upgrade maybe Cheaper, But people are split on moving to Windows 8, make sure you like it befor going to it. It has the look and feel of a touch screen tablet.

The short answer is no.

Recovery disks imply a prebuilt computer (you would not need recovery disks if you have original installation disks) which has an OEM licence, this cannot be installed on another computer. Additionally, there has never been a free upgrade to 7 from any verson of Windows, even during the Honeymoon period when 7 was released and upgrades were pushed so were very cheap.