I don't actually know how well it works, but there is exactly ONE way that I've managed to financially support open source software: offer a version with licens

I don't actually know how well it works, but there is exactly ONE way that I've managed to financially support open source software: offer a version with licenses. For example, my company pays for OpenVPN Access Server not because it offers a ton of value over OpenVPN (it really doesn't, for our use case), but because they provided a way for me to give them money that's acceptable within a corporate budget.