Just got back from Venice with a buddy who has Vz.
He rented a GSM loaner from them for I think $10 and had roaming of $1.99/min incoming and ouTgoing. If its only for true emergency then it wouldnt amount to much.
I bought a Vodaphone SIM for 20 euro with 20 euro credit and 60 eurocent per mn to USA.
John n San Antonio