Where to translate?

[MarcoAurelioWM]

Hi there! I'd like to tweak some Spanish messages. Is this done using https://translation.io? It'd appear so by looking at #565 but I prefered to ask first. Thank you.

[MarcoAurelioWM]

I've been taking a look at translation.io but it's not clear to me if @dqwiki would have to invite me to her translation.io board and, most importantly, if that would cost her money (reading https://translation.io/pricing they say open source projects are free, but next they talk about price per keys).