No first hand experience, but I’ve heard stories of African kids doing impressive tech stuff using very limited resources. Presumably quite a few have access to school computers these days? Developing extensions is free as long as you have access to a computer. Anyway, not having access to a credit card (also need to be capable of international payment, which is not a given) is a much bigger issue than not having $5.
I have $5 but on principle I don't want to give it to Google so that I can make their web browser better.
That with the horror stories about the review process has stopped me from publishing an extension for Chrome.
Edit: there was a nice article on HN last week about how relationships change once you start to have a monetary exchange, which I think suggests I wouldn't be the only one to be irrational about it [1].