First of all, I really appreciate PsychoPy and all the effort you’ve been putting to make this lovable tool available for everyone for free, and I would love to attend to the event. I also love the fact that Pavlovia is made available at an apparently symbolic price.
While on one hand I love Psychopy, on the other hand your pricing policy is unrealistic for a typical Brazilian Master’s student living on a stipend. For instance, the event you are promoting has a price of £300 which is, in my opinion, very fair for someone living in the US or UK, for instance. But for a student on my situation, living on a stipend of 1500BRL (the standard stipend for Master’s level students in Brazil, converting today as £ 201.75) it would mean 1.5 times my stipend. That means I would have to not live at all for one and a half month to attend to the event.
For the sake of social fairness, I would strongly suggest that you think about localized prices for events or even the use of Pavlovia. While .20 GBP per trial might seem a little bit symbolic for someone in the UK, it’s not “that symbolic” for someone outside where exchange rates are not that favorable and where researchers might not work at the same conditions they do in developed countries. If running a 50 participants might cost “just £10”, " just £10" might lack the “just” for half of the world population. But if you just added another .10 GBP to the price you charge people in the US and UK, for instance, and reduced and average of .10 GBP on the price you charge other countries in situations like ours, it would make little or no difference for people in US and UK, while it would make a world of difference for people in those countries.
That said, I still appreciate all the effort put on building PsychoPy and Pavlovia and that means a lot. I am just calling your attention to a problem that might keep limiting science to the developed countries (the very opposite of what Open Science means).