For FLOSS you could let users put donations on an issue, whenever the pot gets large enough for a developer to take interest they'll work on it. That way you don't need to determine a price and you let users decide what features they want by putting their money where their mouth is.
> let users decide what features they want by putting their money where their mouth is
While nice in theory, something like this needs to also have the FLOSS project developers mark requests as feasible and/or within the scope of the project's goals before allowing bounties to be placed on them. Otherwise there is a risk of project hijacking.
Yes, chrome extension so that next to the +1 button is a way to chip in money, and adds a comment to the issue like "seibelj pledged $10 to this issue".
