Just had a email from Wunderlist advertising the 'Pay it forward' bundle. On further investigation, it included a lot more, including one year subscriptions to Pixlr and Sketchbook Pro.
It is a 'pay what you want' contribution with all proceeds going to charity.
Average contribution 'the minimum' was at $9 when I got it (£5.74).
Wunderlist Pro is £34.99 on its own.