Lingua::Translate::Google does not give unlimited access.

https://developers.google.com/translate/v2/pricing states:

"If you need to translate more than 50 M chars/day, please contact us."

The Microsoft Translator also has associated fees: https://datamarket.azure.com/dataset/1899a118-d202-492c-aa16-ba21c33c06cb.

"Is there any other alternative? As good as the Babelfish one?"

Well, Babelfish is gone. There is much discussion about the accuracy of the Microsoft translate results: http://blogs.msdn.com/b/translation/archive/2012/05/30/welcoming-yahoo-babel-fish-users.aspx.