Try Yandex Translator, it is much better suited for Russian translations.
Viewing post in Amelia's Stranded Adventure comments
It almost looks promising, but at the end of the day, use of their API still requires a monthly fee. I would need a solution that relies on the user instead of me I think. If it's possible to let others sign up for an API key and input it into the game to translate, that may work, though I would need to be very careful that it doesn't break terms of service or cause legal troubles.