is there free upgrade from windows vista to 7 ?

I bought a used laptop with vista, I asked the salesman if he could upgrade it to 7 and he said he couldn't because of being in business,but I could do it, and download 7 for free. Can someone guide me to the site ? I just find fake free sites etc.
Thanks.

No, you can't upgrade for free or otherwise. In order to upgrade you will need to purchase Windows 7 and the only version available is Windows 8.1 MS has pulled all other versions of Windows from the shelves. If your laptop with Vista is working well, you just might as well stick with it.