the bill would be horrendus, a lot of sites (if your using sites) have wifi , on some its free on others you pay a charge or use an internet cafe.
On the dongle front vodafone do a deal for europe where you pay 'x' amount for 24hrs access and it is just that 24hrs from when you pay in one stint.
'3' let you use your inclusive allowance if on contract when in Italy and also 3 or 4 other countries where they have 'sister' networks. Two of the countries are denmark and ireland, i cant rememberthe others.
If you will be in a country long enough it might be worth seeing if they have payg dongles for their networks or a simcard for a country your in with an unlocked phone that you can use to connect to your laptop
