RE: What is the minimum
That my friend is a really loaded question!
If you have good footage, a great idea, novel footage, etc.etc.,etc., it doesn't matter how much you spend on equipment.
I've seen first movies from new directors that made them hot hot hot in LA LA LAND and they didn't spend but 7-8 thousand on everything from film stock to processing..
Don't worry about equipment......it's the quality of the show that sells.