Anyone have success with a "pay what you want" model?

I run StampFans – a snail-mail publishing platform. Think Substack, but for snail-mail. Writers set their own subscription fee and keep everything they earn over our $3/month/subscriber fee (this pays for postage, paper, ink, and processing). We've had several hundred people start writing on StampFans over the past few months, and most of them are charging $5/ or $6/month. A few seem to be able to charge more than that, but not many. Then a few are charging just $4/month and keep just $1/month per subscriber. Just now, one of our best writers told me the ideal situation would be for writers to be able to accept a "pay what you want" fee from their subscribers. $3/month would be the minimum (that leaves no profit for the writer), and the subscriber would pick an amount over that. This writer said her friends and family would probably pay well over $6/month, since they see it as a way to support them. But "strangers" probably wouldn't pay more than $4/ or $5/month. Does anyone have experience with a "pay what you want" model? There are a lot of complexities to setting this up, but I'm thinking it might be worth the hassle. I'd love your thoughts or feedback – especially if you've tried this kind of thing before.