Q: Just bought an ipod touch 6 and imovie is not free. How do i get it?

Did you buy it from the Apple Store or from someone?

For iMovie to be free you need to be signed into the App store with the same Apple ID you used to activate that iPod. It's not as much free for the device, it's free for the Apple ID that activates a new device

Maybe it was not brand new.

If it is, follow the instructions below:

Get Pages, Numbers, Keynote, iMovie, GarageBand, and iTunes U for free on your iPhone, iPad, and iPod touch - Apple Supp…

Maybe it was signed in before. Get your refund and buy from Apple retail store.