What? There is no such thing as 'non-free' Debian. The Debian repositories do contain the 'non-free' section which is used to deliver non-free firmware among other things.
There are unofficial "non-free" Debian images (both install and live) that contain said non-free firmware, though. And though they're 'unofficial', they may be needed to enable even fairly baseline features on recent hardware.
I would not trust any unofficial installer. Luckily many problems can be solved with a USB-Ethernet adapter and later configuration of the systen, since the issue usually lies in exotic network hardware.