I am right now waiting for the car to get new tires so I take the occasion to write you my experience about butter.
I always heard my mother and grand mother preaching how easy it was to make butter but I think it was more to tell me that before electricity, you have to make it all by hand and it took maybe hours (or a good pain in the arm). Anyway, I never saw any of them make butter.
I watched on YouTube, found a good video that explained very good, and actually, it did not seem that difficult. You take fat creme fraiche (the fattest you can find) and you mix it during a long time. After a while, take your hand to finish and pof! You have butter! Clean it with very cold water at the end and enjoy your own butter!
4dl creme fraiche for 150gr butter, this is not very economical. But good, give it a try!