I was really pleased with the range of @uzu microgrants, although it was uncompetitive - we were able to fund all the proposals that fit the open call and had enough detail to evaluate.
Crowdfunding for free/open source at this level is tricky because people do it for fun and intrinsic value, it's hardly possible to fund at a market value, and underpaying while placing expectations on what you do (via bounties or whatever) can be a huge demotivator. We came up with a plan for one option on the open call where people could just ask for some money - not as a payment, but just for some recognition for work they've already done - not to say please do this, or to compensate for the weeks and months poured into the project, but just to say thank you. It's still a bit weird that you have to apply to an open call to be thanked though..