"Pay What You Want" should be allowed to start at zero

[kaleidawave]

I have a product but I want the purchase to be more of an optional tip.

Currently I think it is possible by have the two products (with the same benefits) but one being free and one being paid and having a checkout link with the two products. I don't think the discount system would work with variable/custom prices.

I am not sure if there are financial reasons (aka a minimum fee for transaction) for not allowing to start at zero. Instead of >=0.5 there could be an option to disable 0 < amount < 0.5. And when the input is zero then it defaults to the same logic as free products?