I made $6000 in 2018 selling my Ruby book online. It was in my native language, but I'm translating it into English. About half of the book has been translated.

I made $6000 in 2018 selling my Ruby book online. It was in my native language, but I'm translating it into English. About half of the book has been translated. 50% off if you're interested http://leanpub.com/rubyisforfun/c/IQrM7FYyuepX http://leanpub.com/rubyisforfun/c/IQrM7FYyuepX