Yackie or Hop Mobile?...or another?

[teothx]

I'm try to understand what's the best rate to Italy: with international sims or prepaid card, it's not important how...

I say that Hiboo it's cheap because I'll make only (or maybe) mobile to landline (Usa to Italy).
And I don't understand if pingo.com and others works by mobile phone...because I think that are the very best alternatives to international sims