I would be willing to pay EU 50-100 / year for further development, on condition that - if I stop paying - the phone stays at its state and not will become unusable or locked.
I am ready to support Jolla, but under the condition, that the SFOS stays independent and open source.
edit: Better than a monthly or yearly fee would be: pay per every update event.
edit: some people pay abt. 25 Euro every month for some satellite TV channel…