<i>Editorial notes:</i><p>The questionnaire seems to be missing "desktop (GUI) apps" and probably "mobile apps" in "What you'd pay for?" section.<p>Also, the "time/effort" was weird for me; I don't feel it matches "funding" which sounds like money to me — or I didn't understand what it's intended to mean.<p><i>Some general thoughts:</i><p>On a related note, personally I don't like paying until I tried an app. But then OSS apps often ask for payment only just before/after downloading. I think a deferred approach is one of the reasons which helped me pay (donate) for the single OSS app for which I've done so yet: Calibre (<a href="https://calibre-ebook.com/" rel="nofollow">https://calibre-ebook.com/</a>). While the main reason was that it really struck me that it's an awesome, polished and easy to use app (especially for non-technical users in my family) while I was downloading it to <i>n</i>-th computer one day, it also shows some non-obtrusive but visible <i>encouragement</i> in its GUI (a big heart icon — feels encouraging, not nagging) reminding to consider donation.<p>From other somewhat interesting approaches, Aseprite (<a href="https://www.aseprite.org/" rel="nofollow">https://www.aseprite.org/</a>) is actually GPL IIUC, but it provides the binary only with payment — thus more convenient (esp. for non-technical users, who I assume are majority of the targeted users group, i.e. artists) — although you can still just download and compile the sources <i>for free</i>. I'm very curious to what extent it's actually working for the author!<p>Moreover, I felt quite nice about itch.io's (<a href="http://itch.io/" rel="nofollow">http://itch.io/</a>) approach, where a publisher can pick a "payment-optional" model. But as written above, I'd prefer to be <i>gently</i> reminded in-game from time to time (<i>@leafo?</i> whaddya think? feature idea for Refinery?). Also, I didn't really find a good enough game for me on itch yet, for which I'd feel like paying, unfortunately.<p>Finally, I think it'd be easy for me to pay for OSS games (dunno about other apps?) which would be parts of a bundle (ideally on gog.com; maybe Humble Bundle too, but as much as it started the bundles trend in awesome way, I feel it's fallen in quality and open-ness for me at some point in the past). I'm already paying for bundles, so if an OSS game got in there, I probably wouldn't even notice I can have it for free (nor I would complain later if I noticed, I believe). Though if it'd be explicit, I think I'd pay anyway (custom? convenience?).<p><i>P.S.</i> Now that I think of it, seems what I describe here is kinda variation of "in-game/in-app purchases". Hm, maybe they could be also linked to some specially tricky features of an app, e.g. using some feature would also display non-obtrusive info "this feature was really tricky/took much love to implement/and is unique on market — a donation as act of gratitude would be an awesome gesture of appreciation!" obviously with an easy link.<p>Also, I think receiving a code enabling personalized label/annotation "Paid for by $DONATING_USER" could be a really cool bonus touch.