First off, I'm very grateful that the Hubski team is willing to cover the costs so far. I've seen a couple of great sites / projects evaporate because of financial issues. Thanks everyone. My opinion is that having a donation button would be nice and I think there are enough users who'd want to donate (myself included). I don't think it's a good long-term option, though. Donations are sporadic and it's not something that alleviates the financial worry / stress. Merch is in the same category - it's nice to have, but not something stable to build a site on. That's why I think a monthly donation option would be better, name-your-price style. Just don't make it visible publically, or only make it visible to the user who's donating as a reminder. It shouldn't be a badge of honor. The only reason people should support the site is because they want to support the site.
I thought that Patreon was paying per creation, something that doesn't make sense for supporting a site. But after checking their site, it turns out that they have a monthly support option. mk, what do you think about setting up a Patreon page for hubski? Without perks, that is. While I still like kleinbl00's suggestion of a bounty on features, I think there are more than enough people who either a) don't really have feature requests or b) just want to support hubski any way they can. And it's far easier to set up.