Simple accounting software for voluntary organisation?

I see a thread from @ohlalalala last March has gone unanswered, but let me try again:

This is for a small non-profit organisation with no employees, just volunteers, that has to handle members subscriptions, event fees, professional fees, printing, website costs, etc.

Any suggests for accounting software? There is a spreadsheet at the moment but it's too messy and hard for a non-techy person to understand and trace the figures. Ideally free software, but maybe a low-cost one, say 10-20 euro per month, probably online so the job can be passed around the treasurer's role as it is rotated each year or two.

TIA

P