I wondered if you'd considered Patreon <http://patreon.com
>? It's a site for setting up small, periodic, donations for creative projects. It's designed to be used alongside a free "product" (such as a youtube's videos or a game devs updates). Sometimes small perks are offered for Pateron supporters but generally speaking whatever an artist or creator offers is the same whether someone has donated or not. In the past couple of years it has become very popular, partically for podcasters, youtubers & comic artists.
I've just found nzb360 and love it. Seeing that you've made PRO free indefinitely, I (semi-paradoxly) want to pay you money. You've mentioned in the FAQ subscription model is off the table but I was wondering if you'd consider setting up a Patreon account as it would be an optional subscription. Donations are traditionally very low (90% of the creator I support, I pledge $1 per month).
Anywho, keep up the good work.