You need to study the time value of money in finance. Concepts such as the Net Present Value and the Internal Rate of Return. Nothing is ever really free. The youtube videos on free energy are by idiots for idiots.
Agree nothing in life including energy is 'free'. However if you mean being off-grid or generating power/heat to become self sufficient there are any number of technologies... none are 'free' all have some cost associated. Wind and solar are obvious ones, but depending on where you live and what feedstock you have avaliable you might consider biogas or gasifier. Plans and information on the latter are available at www.build-a-biogas-plant.com
www.build-a-gasifier.com
There's no such thing as "free energy", no matter in what sense.
Companies or people that claim they have devices that can create energy are simply lying, and devices that don't break the laws of physics have not been successful yet.
Nothing is free. You can make use of passive solar by making use of lots of insulation and energy efficient windows and doors that face South.
