TrueNAS is a hardware and software combo that you can optionally buy support on. You'd be kind of silly to buy TrueNAS and not support, but there is nothing stopping you from doing that, even if it is somewhat illogical. ;)
If you are wanting to buy good hardware for FreeNAS, but want to do your own support you can look at "FreeNAS certified" hardware from iXsystems.
