Gadget/Tech Channel videos

Hi guys. Wanna get a faceless Tech/Gadget channel started. Few quick questions:

Are you allowed to use the videos from Amazon's site on YouTube if edited? Or what's the best way if you wanna promote their products?

For products aside from Amazon what's the method for using videos without copyright issues?
I see some American gadget channels using Chinese videos - does this get around copyright?

Any other help appreciated!

Thanks

Sig